http://www.cfd-online.com/W/index.php?title=Special:Contributions/Jasond&feed=atom&limit=50&target=Jasond&year=&month=CFD-Wiki - User contributions [en]2016-05-30T16:47:15ZFrom CFD-WikiMediaWiki 1.16.5http://www.cfd-online.com/Wiki/Talk:Reynolds_numberTalk:Reynolds number2007-08-30T21:12:36Z<p>Jasond: </p>
<hr />
<div>I'm a bit hesitant if we should add so many links to non-existent pages. It will only be confusing and make the text more difficult to read. A few non-existent links to really important pages is okay I think, but then we should start filling the non-existing links with content instead of adding more non-existent links. At least that is my opinion. Or what do you think? --[[User:Jola|Jola]] 01:21, 24 August 2007 (MDT)<br />
<br />
: I had hoped that I would not be the first to respond to this, but I agree that too many links to non-existent pages is a bad thing. Now, I think that we probably should have articles on some of these things, or at least we should be doing a better job of inter-article linking - I just set the momentum equation link to the Navier-Stokes article (which probably needs to be a link within the article rather than to the whole thing). My opinion is this: we do need more interarticle links, but we should be filling in material as we go. --[[User:Jasond|Jasond]] 15:12, 30 August 2007 (MDT)</div>Jasondhttp://www.cfd-online.com/Wiki/Reynolds_numberReynolds number2007-08-30T21:10:07Z<p>Jasond: </p>
<hr />
<div>The Reynolds number characterises the relative importance of inertial and viscous forces in a flow. It is important in determining the state of the [[flow]], whether it is [[laminar]] or [[turbulent]]. At high Reynolds numbers flows generally tend to be [[turbulent]], which was first recognized by [[Osborne Reynolds]] in his famous [[pipe flow experiments]]. Consider the [[Navier-Stokes equations|momentum equation]] which is given below<br />
<br />
:<math><br />
\frac{\partial}{\partial t}\left( \rho u_i \right) +<br />
\frac{\partial}{\partial x_j}<br />
\left[ \rho u_i u_j + p \delta_{ij} \right] = \frac{\partial}{\partial x_j} \tau_{ij}<br />
</math><br />
<br />
The terms on the right are the [[inertial forces]] and those on the left correspond to [[viscous forces]]. If <math>U</math>, <math>L</math>, <math>\rho</math> and <math>\mu</math> are the reference values for [[velocity]], [[length]], [[density]] and [[dynamic viscosity]], then<br />
<br />
inertial force ~ <math>\frac{\rho U^2}{L}</math><br />
<br />
viscous force ~ <math>\frac{\mu U}{L^2}</math><br />
<br />
Their ratio is the Reynolds number, usually denoted as <math>Re</math><br />
<br />
:<math><br />
Re = \frac{\mbox{inertial force}}{\mbox{viscous force}} = \frac{\rho U L}{\mu}<br />
</math><br />
<br />
In terms of the kinematic viscosity<br />
<br />
:<math><br />
\nu = \frac{\mu}{\rho}<br />
</math><br />
<br />
the Reynolds number is given by<br />
<br />
:<math><br />
Re = \frac{U L}{\nu}<br />
</math><br />
<br />
==Reynolds number as a ratio of time scales==<br />
<br />
Consider an impulsively started flat plate moving in its own plane with [[velocity]] <math>U</math>. Due to the [[no-slip condition]] on the plate a [[boundary layer]] gradually develops on the plate. At time <math>t</math>, the thickness of the [[boundary layer]] is of the order of <math>\sqrt{\nu t}</math> (see Batchelor(1967), section 4.3). Let <math>L</math> be the [[characteristic length scale]]. The time taken for [[viscous]] and [[convective]] effects to travel a distance <math>L</math> is<br />
<br />
:<math><br />
T_{v} = \frac{L^2}{\nu}<br />
</math><br />
<br />
and<br />
<br />
:<math><br />
T_{c} = \frac{L}{U}<br />
</math><br />
<br />
The ratio of viscous to convective time scales is<br />
<br />
:<math><br />
\frac{ T_{v} }{ T_{c} } = \frac{(L^2/\nu)}{(L/U)} = \frac{UL}{\nu} = Re<br />
</math><br />
<br />
Thus the Reynolds number is a measure of the viscous and convective time scales. A large Reynolds number means that viscous effects propagate slowly into the [[fluid]]. This is the reason why boundary layers are thin in high Reynolds number flows because the fluid is being convected along the [[flow]] direction at a much faster rate than the spreading of the [[boundary layer]], which is normal to the [[flow]] direction.<br />
<br />
==References==<br />
*{{reference-book | author=Batchelor G K | year=1967 | title=An Introduction to Fluid Dynamics | rest=Cambridge University Press}}<br />
<br />
[[Category: Dimensionless parameters]]</div>Jasondhttp://www.cfd-online.com/Wiki/Fluent_FAQFluent FAQ2007-08-24T00:36:01Z<p>Jasond: /* Post-Processing Related */</p>
<hr />
<div>This article contains questions and answers on the use of Fluent products (mainly Fluent and Gambit). Please feel free to add questions and answers here!<br />
<br />
== General Information ==<br />
<br />
=== What is Fluent? ===<br />
There are two answers to this question: Fluent (the company) is a CFD software company that is now part of ANSYS Inc. Fluent (the software package) is a popular commercial CFD package.<br />
<br />
=== What is Gambit? ===<br />
Gambit is a meshing software package that is typically purchased{{Fact}} with Fluent.<br />
<br />
=== How can I learn Fluent and Gambit? ===<br />
<br />
The documentation provided by Fluent is actually quite good, so it is a very good place to start. Fluent also provides tutorials and documentation<br />
on the [http://www.fluentusers.com fluentusers] site, which is open to everyone with a<br />
(full) license. Without a full commercial license, it is possible to use the tutorials given at [http://www.studentfluent.com/ studentfluent], or you may be able to register to use the user services center through other channels (e.g. through the university program). There are also some good tutorials available at [http://instruct1.cit.cornell.edu/courses/fluent/index.htm Cornell] and at various other places on the web (Google is a good place to start).<br />
<br />
=== Using CFD-Online's Fluent Forum ===<br />
<br />
==== How should I ask my question on the Fluent forum to get the most useful answer? ====<br />
<br />
It is important to understand that the quality of the answer to your question depends upon how well you ask your question. Many of the questions posted on the Fluent forum are so poorly posed that it is very difficult to understand what the poster is actually asking. Here are some suggestions to avoid this problem:<br />
<br />
# Make sure your question is as clear, concise, and as specific as possible. Other forum readers are unlikely to spend time trying to decipher a garbled question.<br />
# Give a clear general description of what class of problem and/or application you are working on before you start asking specific questions. This will aid other forum readers to better understand your specific questions.<br />
# Describe precisely what you have done yourself to try and solve your problem, giving examples.<br />
# Depending on your problem, you should try to include the following:<br />
#*If you are asking a mesh quality related question then include some sample images of your mesh, including the boundary layer.<br />
#*If you are asking a UDF question then include a copy of your existing code file as an attachment or in your post using <nowiki><pre></nowiki> tags to keep the code legible.<br />
<br />
==== How do I upload images? ==== <br />
* Create the image on your local machine e.g. skew_mesh.jpg<br />
* Upload the image to [http://www.imageshack.us Imageshack]<br />
* Copy the link "Thumbnail for websites"<br />
* Paste the link into your post e.g. <i><nowiki><a href="http://img91.imageshack.us/my.php?image=pipeym8.jpg" target="_blank"><img src="http://img91.imageshack.us/img91/5681/pipeym8.th.jpg" border="0" alt="Free Image Hosting at www.ImageShack.us" /></a></nowiki></i><br />
<br />
==== How do I share non-image files as attachments? ====<br />
* If you have more than one file, zip them into a single file.<br />
* Upload the file to [http://www.rapidshare.de Rapidshare] [http://www.gigasize.com/ Gigasize]<br />
* Scroll down to "I don't want a collector's account right now. Just give me the download-link." and click it.<br />
* Scroll down until you see the link e.g. <i><nowiki>http://rapidshare.de/files/33808646/audio.log.html</nowiki></i><br />
<br />
== FLUENT ==<br />
=== Solver Related ===<br />
==== What does "floating point error" mean? How can I avoid it? ====<br />
<br />
The floating point error has been reported many times and discussed a lot. Here are some of the answers found in the Fluent Forum:<br />
<br />
From numerical computation view point , the basic operations performed by computer are represented inside computer in what is called floating point numbers. The errors that are either because of invalid numeric computation initiated by user or limitation of machine that is used are floating point errors.<br />
<br />
1)Invalid Operations:- Simplest example is if one uses Newton Raphson root finding method to solve f(x)=0 and for some Nth iteration if we get x = x(N) such that derivative of function f(x), f'(x(N))=0 then formula for calculating next iterate x(N+1) = x(N) - f(x(N))/f'(x(N)) requires division by f'(x(N)) which is zero. Here you get divide by zero type of floating point error.<br />
<br />
2) Over or Underflow:- Another type is having data with either too large or too small magnitude called 'overflow' or 'underflow' respectively.Such data cannot be physically represented on computer for direct processing by arithmetic processing part of Processor. <br />
<br />
3) Rounding off errors :- While rounding off a decimal number , some significant digits are lost which cannot be recovered .<br />
e.g. if we round off 0.1 to integer (not greater than it called 'floor' of the given no.) then it is zero. If this value if further used for computation then it may lead to several errors.<br />
<br />
'''SOLVER AND ITERATION''' -----I think if you set shorter time step, it may be good. Or changing little Under-Relaxiation-Factors, it may be good. In my experience, I set 1/3 Under-Relaxiation-Factors as default.� -----�also lower the values of under relaxation factor and use the coupled implicit solver� -----�Try to change under-relaxation factors and if it is unsteady problem maybe time step is to large.� -----�you can improve the ratio in the solve--control--limits, maybe that can help.� -----�you will need to decrease the Courant number� -----�If you still get the error, initialize the domain with nothing to 'Compute from...' Then click 'init'. Again select the surface from which you want to compute the initial values & iterate. This should work.� -----�Another reason could be a to high courant number - that means, that the steps between two iterations are too large and the change in the results is too large as well (high residuals)�<br />
<br />
'''GRID PROBLEMS''' -----�this error comes when I start scaling grid. in gambit, all my dimension is in mm, when in fluent i convert it in meter using buttone SCALE. after it, when i iterate, about hundred iteration, this error appeared. but when i not scale my drawing to m...and let it be as in gambit..then the iteration is success. -----�hi I think you should check your mesh grid mesh is very high. your problem solve by selection a low mesh.� -----�Your mesh is so heavy that your computers resources are not enough. try to use coarser mesh.�<br />
<br />
'''BOUNDARY CONDITIONS''' -----�In my case I had set a wall boundary condition instead of an axis boundary condition and then FLuent refuses to calculate telling me 'floating point error'.� -----�Your Boudary Conditions do not represent real physis.� -----�wrong boundary condition definition might cause the floating point error. For example setting an internal boundary as interior� -----�Once I had the problem, simulating a 2D chamber with a symmetry BC. I set the symmetry somewhere as �axe symmetric� and the floating point error occur� -----�check the turbulence parameter you set. reduce the turbulence intensity to less that one for first, say 50 iterations.<br />
<br />
'''MULTI PROCESSOR ISSUES''' -----"I've had similar problems recently with floating point errors on a multi processor simulation. The solution for my problem seems to be to run on a single processor, where it runs fine....?�<br />
<br />
'''WRONG INITIATION''' ----- Initiating the case with wrong conditions may lead to floating point error when the iterations start.<br />
<br />
==== What is the difference between the coupled and the segregated solver? ====<br />
In the latest Fluent release,6.3.26 these are referred as density based and pressure based solvers.<br />
<br />
The coupled solver will solve all equations (conservation equations for mass, momentum and energy) simultaneously instead of sequentially (the equations are segregated from one another). You should use the coupled solver when the velocity and pressure are strongly coupled (high pressures and high velocities), but very long calculation times may be required when you use the coupled solver.<br />
<br />
In the coupled solvers, the Species Diffusion Term is always included in the energy equation.<br />
<br />
When you use the segregated solver, FLUENT allows you to specify anisotropic conductivity for solid materials<br />
<br />
From the [http://www.cfd-online.com/Forum/fluent_archive.cgi?read=40127 Fluent forum]:<br />
<br />
Choice of solvers depends heavily on the model being solved. The segregated solver solution is based on the pressure, while the coupled solver solution is based on density. This makes the segregated solver better at low speed flows and the coupled solver better at solving transonic / supersonic cases. I wouldn't recommend the coupled solver at any flows below Mach .4 (until the pressure based coupled solver comes out in the next release of Fluent). I've used the Segregated solver up to Mach 1.5 with great results, but the higher speed, the more mesh dependent you become (because the segregated solver tends to "smooth out" shocks), so you have to pay a lot of attention to your meshing.<br />
<br />
The coupled solver tends to be more stable with the defaults settings. The segregated solver tends to be very sensitive to the allowable limits. When trying to get a solution with the segregated solver, DO NOT increase the turbulent viscosity ratio limit (unless you have a great reason to based on past experience or the physics of your current model truly exceeding that limit, but I've never even heard of that being realistic). Instead limit the pressure and temperature limits to reasonable limits (i.e. Plimits = Pstatic +/- (2 * dynamic pressure), and calculate the appropriate temps). You need to give the solution "room to move" while it reaches a solution, but you don't want to give it enough room where it goes out to some totally impossible numbers, and the limits help prevent this.<br />
<br />
=== Model Related ===<br />
==== What is the turbulent viscosity ratio warning and how can I handle it? ====<br />
The problem can be caused by improper values for the boundary condition turbulence parameters. Check the fluent manual (which is kind of more like a textbook), about modeling turbulence.<br />
<br />
For the case of internal flow, you basically have to consider the physical state of the fluid upon entrance to your control volume. If the fluid is coming into your volume from a fully developed turbulent pipe flow, it will have more turbulent energy than from a stagnant fluid. Think of lots of little vortices, which mostly mix things up, and those all have kinetic energy associated). This energy can be expressed as a nondimensional Intensity (a percentage is used). In addition, a Length parameter is specified.<br />
<br />
==== How can I determine the inputs for a porous media or porous jump from flow versus pressure drop data? ====<br />
If you have pressure drop versus velocity data, you can fit the following equation through the data:<br />
<br />
<math>\Delta P = Av^2 + Bv</math><br />
<br />
where <math>\Delta P</math> is the pressure drop and <math>v</math> is the velocity. The coefficients <math>A</math> and <math>B</math> are related to the Fluent variables for the permeability <math>\alpha</math>, and the pressure coefficient <math>C_2</math> by<br />
<br />
<math>A = \frac{C_2 \rho \Delta n}{2}</math> and <math>B=\frac{\mu}{\alpha}\Delta n</math><br />
<br />
where <math>\Delta n</math> is the thicknes of the medium.<br />
<br />
==== How do I model heat conduction in a composite wall? ====<br />
<br />
==== What pressures should be specified at inlets and outlets for buoyancy flow problems? ====<br />
<br />
what pressures at inlet and outlet should specified in natural convection?<br />
<br />
==== Are there any general guidelines on selecting a turbulence model? ====<br />
<br />
==== How can both turbulent and laminar flow be included in one model? ====<br />
<br />
Depends. Fluent cannot presently compute boundary layer instability and subsequent transition to turbulence using a RANS approach (ke, SST, RSM etc). CFX has a new feature to do this, so perhaps it will be incorporated into Fluent soon as they are both owned by ANSYS.<br />
<br />
You therefore have two options : <br />
<br />
1. If you know the point of transition (like on an aircraft wing) from experimental data or DNS simulations, you can impose laminar flow in some regions by meshing a separate fluid region, and enabling "laminar zone" for this region in boundary settings. That is also useful in heat transfer cases, if for example you have turbulent flow one side of a thermal wall, and natural convection on the other side.<br />
<br />
2. A "near-wall" turbulence approach : Either k-omega, SST, or Low Reynolds k-E (which you have to select from the "Turbulence modelling/expert" menu), will damp turbulence near to the wall, either by empirical damping of turbulent "k" (Low Reynolds k-E) or by full solution of the omega equation on a fine enough mesh (k-omega/SST). If you have flows in small gaps in a larger, turbulent domain, in which large lengthscales of turbulence of course could not be supported, the flow will re-laminarise in a physically sensible (although perhaps not mathematically exact) manner. These models will also MAINTAIN laminar flow in external boundary layers, PROVIDED that you have a fine enough mesh (use the laminar mesh distribution guidelines in Fluent manual, too coarse a mesh will lead to non-physical turbulence generation in the BL). BUT they will maintain this laminar flow and evolution of the laminar profile (in the absence of significant disturbance by separation or impingement at the wall) forever, no spontaneous instability or transition to turbulence will occur. So check the length-based Reynolds numbers of walls where you think there will be undisturbed laminar boundaries, that there is not expected to be spontaneous transition of these BLs.<br />
<br />
==== How to start a 3D simulation with an compressible medium and temperature changes? What is important to consider ====<br />
<br />
<br />
I would do it that way:<br />
<br />
1. solve the flow for incompressible medium, without energy equation. Set the density close to the density, that you expect at the present pressure and temperature. The solution for the flow dosn't has to be completely convergent, but the residuals should be on the way down. <br />
<br />
2. Apply energy equation and compressibility of the gas and set the present pressure with operating condition option. You might do some iteration steps as well. Sometimes they are not necessary<br />
<br />
3. Apply the thermal BC<br />
<br />
=== Solution Methodology === <br />
==== How do I carry out rotating body analysis, eg a rotating sphere or cylinder''' in flo'''w? ====<br />
Rotating cylinder problem ( assume circular ), can be done easily by specifying angular velocity on the cylinder wall. As i observed no need of moving mesh for this case. you need to specify the rotation axis with respect to which your cylinder is rotating.<br />
<br />
==== How do I get better and faster convergence? ====<br />
==== What is the role of under-relaxation parameters? What should be the optimum choice of these parameters? ====<br />
They limit the influence of the previous iteration over the present one. If you choose small values it may prevent oscillations in residuum developing. At the same time the solution may need more time to converge. <br />
Keep the default values as they are given in FLUENT. You can decrease them gradually if necessary. Momentum 0.6, pressure 0.1, k 0.4, eps 0.4, mass source 1, viscosity 1.<br />
<br />
=== User-Defined Function (UDF) Related ===<br />
<br />
==== How do I learn UDF programming? ====<br />
There are not to many tutorials out there on this, probably due to the wide variety of things you can do with the UDF interface. The documentation the Fluent provides is pretty good once you know what you are trying to do (chapter 8 of the UDF manual has examples). UDF programming is easier if you have C programming experience, so it is advisable to learn a little C programming, then do some of the simple cases that Fluent provides, then tackle the problem you really want to solve. <br />
<br />
==== How do I create/build/load a UDF? ====<br />
The simplest way to add a UDF into Fluent is to write your UDF in the C programming language and then use Define -> User-Defined -> Functions to either interpret or compile your UDF. It can then be loaded. Fluent provides good documentation of the UDF interface with numerous examples, so read that before trying too much.<br />
<br />
==== Do I have to use C? ====<br />
Yes and no. To hook your UDF into Fluent, you'll probably have to use one of the DEFINE_* macros that Fluent provides, and this is most easily done using C. However, you can write routines that are used in the routines that are defined with the DEFINE_* macros in other languages and then link them together. This requires some knowledge of mixed language programming, Makefiles, the text user interface (TUI), and is not necessarily very portable. An example using Fortran is given in Section 5.4.1 of the Fluent UDF Manual (version 6.3).<br />
<br />
==== Which compilers work? ====<br />
On Unix-like machines, GCC is the compiler of choice. On Windows machines, Microsoft Visual C++ is the compiler of choice (GCC may also work on Windows- if anyone has firsthand knowledge of this, please share). The free Express Edition of the Microsoft compiler also works.<br />
<br />
==== My UDF won't interpret or compile - what is wrong? ====<br />
The answer depends upon what exactly has happened. <br />
<br />
*If Fluent complains about not being able to find a compiler, then check to make sure that the compiler is properly installed. On Windows machines, it is possible to install the Visual C++ compiler without fully setting up the command line compiler (which Fluent needs to be able to find). During the installation process, you need to select the "register environment variables" option. Failure to do so will likely lead to complaints about things being "not recognized as an internal or external command, operable program or batch file" or missing DLL's. It is theoretically possible to fix this issue by setting the appropriate environment variables, but keep in mind that even when nmake can be found there still may be DLL issues. The easy path is probably reinstallation of Visual Studio (taking special care to make sure that the command line interface is set up properly), but the reinstallation path is always perilous. If you have long-term experience using Windows you should probably know the risks, and if you don't you should consult an expert.<br />
<br />
*If you are interpreting, keep in mind that not everything that is supported for compiled UDF's is supported for interpreted UDF's. This is true both for the UDF interface and the C language. If you are doing something pretty involved and it fails inexplicably, try compiling to see if that makes a difference.<br />
<br />
*There is also the possibility of coding errors. Keep in mind that your source code gets run through the C preprocessor (to change the Fluent macros into C code), so unintended interactions are very possible.<br />
<br />
==== Why do I get the message "'nmake' is not recognized as an internal or external command, operable program or batch file"? ====<br />
This is a Windows/Visual Studio issue. In order to compile your UDF, Fluent needs to know where the nmake program is located, and it currently can't find it. If you open up a command window and enter "nmake", you should probably get the same message. See the previous question/answer.<br />
<br />
==== My UDF interprets/compiles but fails to execute - what is wrong? ====<br />
This commonly occurs due to a faulty operation of some kind. For example, user-defined memory (UDM) is not allocated until initialization, so attempting to access a UDM variable before initialization can lead to a segmentation fault. Try to isolate the cause, and then look for places where your expectation of what is available may not match reality. Finally, keep in mind that if you do something really bad, you may need to restart Fluent before even a fixed UDF will work.<br />
<br />
=== Post-Processing Related ===<br />
==== What is the best way to generate an animation? ====<br />
There are several ways to do this (both inside and outside of Fluent), and all have merits, so there is probably no "best" way. There are two approaches to using Fluent to generate the graphics: use Fluent to generate the movie (using Solve->Animate->Define...) or use Fluent to generate individual frames of an animation (by generating a hardcopy image at appropriate intervals, then assemble the animation with an external program. Many available postprocessing tools (e.g. Tecplot) can also generate animations, so saving complete data files for use with the postprocessor can also be a path to a animation.<br />
<br />
==== What hardcopy format should I use? ====<br />
The answer here depends upon what you need. For maximum accuracy, use a lossless format (e.g. PPM). The disadvantage of the lossless formats is usually the size of the files. For smaller file size, use a format like JPEG, which will lose some detail. In some cases, the loss of detail will not be be easy to see, while it may be in others.<br />
<br />
=== Journal File and Text User Interface (TUI) Related ===<br />
==== What is the Text User Interface? ====<br />
The Text User Interface (TUI) is a command-line-like interface to Fluent. The TUI is accessed through the main Fluent (hit enter while in the main Fluent window), with a menu system and the ability to execute Scheme programs. Fluent's documentation compares the menu system to the UNIX directory structure. Since it is text base, you can create and modify sequences of TUI commands using a simple text editor (see journal files below).<br />
<br />
When Fluent starts, you are in the "root" menu: press enter and you'll see something like this:<br />
<pre><br />
><br />
adapt/ file/ report/<br />
define/ grid/ solve/<br />
display/ parallel/ surface/<br />
exit plot/ view/<br />
</pre><br />
To access the plot menu, just type in "plot" and then press enter. To bring up the available commands, press enter again:<br />
<pre><br />
> plot<br />
<br />
/plot> <br />
change-fft-ref-pressure file-set/ residuals<br />
circum-avg-axial flamelet-curves residuals-set/<br />
circum-avg-radial histogram solution<br />
fft histogram-set/ solution-set/<br />
file plot<br />
file-list plot-direction<br />
</pre><br />
<br />
To exit a menu, simply type "q" and press enter (the rough equivalent of "cd .." in Unix). The TUI also understands command abreviations, so "pl/rs" is interpreted as "plot/residuals-set".<br />
<br />
==== What is a journal file? ====<br />
A journal file is a series of TUI commands stored in a text file. The file can be written in a text editor or generated by Fluent as a transcript of the commands given to Fluent during your session. A journal file generated by Fluent will include any GUI operations (in a TUI form, though). This is quite useful if you have a series of tasks that you need to execute, as it provides a shortcut. To record a journal file, start recording with File -> Write -> Start Journal..., perform whatever tasks you need, and then stop recording with File -> Write -> Stop Journal...<br />
<br />
==== How do I add a comment in a journal file? ====<br />
Any line beginning with a ''';''' (semicolon) is treated as a comment.<br />
<br />
==== How do I set boundary conditions? ====<br />
Suppose we have a boundary named "south" that we want to set as a wall. The command is<br />
<pre><br />
/define/boundary-conditions/zone-type south wall<br />
</pre><br />
which sets the zone "south" as a wall. The details (moving wall, etc.) can then be accessed be executing<br />
<pre><br />
/define/boundary-conditions/wall south<br />
</pre><br />
in the text user interface.<br />
<br />
==== How do I write a XY-plot? ====<br />
look at<br />
http://www.cfd-online.com/Forum/fluent_archive.cgi?read=40200<br />
<br />
==== How do I set material properties? ====<br />
look at http://www.cfd-online.com/Forum/fluent_archive.cgi?read=38768<br />
<br />
one example:<br />
<br />
<pre><br />
//define/materials/delete<br />
air_50c<br />
//define/materials/delete<br />
air_1bar<br />
//define/materials/change-create<br />
air<br />
air_1bar<br />
y<br />
incompressible-ideal-gas<br />
y<br />
piecewise-linear<br />
2<br />
298.15<br />
1007<br />
323.15<br />
1008<br />
y<br />
piecewise-linear<br />
2<br />
298.15<br />
0.02606<br />
323.15<br />
0.02788<br />
y<br />
piecewise-linear<br />
2<br />
273.15<br />
1.72E-05<br />
433.15<br />
2.45E-05<br />
n<br />
n<br />
n<br />
n<br />
n<br />
n<br />
y<br />
</pre><br />
<br />
==== How do I generate a hardcopy of a window? ====<br />
<br />
<pre><br />
display set-window 1 ; if window nr. 1 is the window you want to be hardcopied<br />
//display/set/windows/scale/form ; setting the options for the graph (colourmap)<br />
"%0.2f"<br />
//display/set/color-ramp<br />
bgr<br />
//display/set/hardcopy/color ; setting the options for the window<<br />
color<br />
//display/set/hardcopy/driver<br />
tiff<br />
//display/set/hardcopy/y-res<br />
2400<br />
//display/set/hardcopy/x-res<br />
3106<br />
//display/set/hardcopy/inv<br />
no<br />
//display/hard<br />
filename.tiff<br />
//display/set/hardcopy/inv<br />
yes<br />
//display/hard<br />
filename_inv.tiff<br />
</pre><br />
<br />
==== How do I run multiple cases in batch mode? ====<br />
This could be achieved by running it from journal file. The example journal file that runs two cases is given as:<br />
<pre><br />
file read-case-data xxx1.cas<br />
solve dual-time-iterate yyy1<br />
file write-case-data zzz1.cas<br />
file read-case-data xxx2.cas<br />
yes ; for discard cas dialog<br />
solve dual-time-iterate yyy2<br />
file write-case-data zzz2.cas<br />
</pre><br />
<br />
<br />
Another example:<br />
<pre><br />
rcd filemname.cas<br />
yes<br />
it 10000 <br />
wcd filemname.cas <br />
yes<br />
</pre><br />
<br />
<br />
Have a look at this discussion: [http://www.cfd-online.com/Forum/fluent_archive_2005.cgi/read/32615 http://www.cfd-online.com/Forum/fluent_archive_2005.cgi/read/32615]<br />
<br />
==== How do I loop in a journal file? ====<br />
The best way to loop in a journal file (or the text user interface) is to use one of the Scheme programming language's looping constructs.<br />
<br />
=== Tips === <br />
==== How do I merge two mesh files into one mesh file? ====<br />
To merge two mesh files the suggested utility is tmerge. The syntax of tmerge is simple.<br><br />
<i>utility tmerge -3d file1 file2 finalfile </i> <br><br />
To join the two interior faces use: <br><br />
<i>Grid->Fuse</i> <br><br />
from the menu with Fluent.<br />
<br />
==== How do I export Fieldview data for postprocessing during iterations? ====<br />
<br />
This could be done with the help of menu <b>solve->Execute Commands </b>. <br />
Here are two examples:<br />
<br />
'''Steady Case'''<br />
<br />
<pre><br />
file/export/fug/File_grid-%n<br />
file/export/fud/File_data-%n pressure velocity-magnitude x-velocity y-velocity z-velocity () </pre><br />
<br />
'''Unsteady Case'''<br />
<br />
<pre><br />
file/export/fug/File_grid-%t<br />
file/export/fud/File_data-%t pressure velocity-magnitude x-velocity y-velocity z-velocity () </pre><br />
<br />
You can chose the frequency of export from the <b>Execute Command</b> panel.<br />
<br />
==== What does abbreviation X mean?====<br />
<br />
{| border="1"<br />
|- <br />
| APG || adverse pressure gradient<br />
|- <br />
| BC || Boundary Conditions<br />
|- <br />
| B-L || Boundary Layer<br />
|-<br />
| CFD || Computational Fluid Dynamics<br />
|-<br />
| DES || Detached Eddy Simulation<br />
|-<br />
| DPM || Discrete Phase Model<br />
|-<br />
| FDM || Finite Difference Method<br />
|-<br />
| FEM || Finite Element Method<br />
|-<br />
| FVM || Finite Volume Method<br />
|-<br />
| GUI || Graphical User Interface<br />
|-<br />
| LES || Large Eddy Simulation<br />
|-<br />
| MUSCL || Monotone Upstream-centered Scheme for Conservation Laws<br />
|-<br />
| MDM || Moving and Deforming Mesh<br />
|-<br />
| PDF || Probability Density Function<br />
|-<br />
| QUICK || Quadratic Upstream Interpolation for Convective Kinematics<br />
|-<br />
| RANS || Reynolds Averaged Navier-Stokes<br />
|-<br />
| RSM || Reynolds Stress Model<br />
|-<br />
| SIMPLE || Semi-Implicit Method for the Pressure-Linked Equation<br />
|-<br />
| SST || Shear Stress Transport<br />
|-<br />
| TUI || Text User Interface<br />
|-<br />
| UDF || User defined function<br />
|-<br />
| URF || Under Relaxation Factor<br />
|-<br />
| VOF || Volume Of Fluid<br />
|}<br />
<br />
==== What is the difference between FE and FV?====<br />
<br />
See the answer in the [[General CFD FAQ#What is the difference between FEM, FVM and FDM?|General CFD FAQ]].<br />
<br />
== FloWizard==<br />
<br />
== FIDAP==<br />
<br />
== POLYFLOW ==<br />
<br />
== Gambit ==<br />
===Why does Gambit refuse to open my .dbs file and say that my file is already open? I get an error message - ERROR: IDENTIFIER "X" CURRENTLY OPEN.===<br />
Before opening your file "X.dbs", Gambit looks for a file named "X.lok" to determine the status of your file. If it finds the .lok file, you'll get the above error message (or something like it). If you are in a multi-user environment, you should check that it is not actually already open elsewhere, but in other situations the most likely reason that there is still a X.lok file is that Gambit encountered a problem the last time X.dbs was open. Deleting the .lok file should solve your problem.<br />
<br />
===Q: Why does Gambit complain about the number of nodes on edges being odd and then refuse to mesh a face?===<br />
<br />
A: It is mathematically impossible to create an all-quad mesh with an odd number of intervals on the outer edge loop. If this is inconvenient for you, you may consider a quad-dominant mesh (mostly quads, with a few triangles), or even an all-triangle mesh. Many users achieved good solutions with triangle surface meshes and prism (wedge) boundary layers.<br />
<br />
===Q: What are these boundary layers things defined in Gambit? Do they represent the real situation?===<br />
<br />
A: Gambit's boundary layers allow you to generate specific semi-structured grids topologies on faces that grow out from an edge or edges. You can specify the initial cell height, the growth rate, and a transition pattern that changes the edge-parallel interval count. There are several default settings, which can affect the quality of boundary layers. For cases with sharp corners, normal and offset smoothing can greatly improve quality. Such smoothing is off by default because it requires significantly more computation time.<br />
<br />
===Q: If my quad face mesh has cells with high skewness or large aspect ratios, the pyramiding procedure used by the tet mesher will frequently lead to failure, why? ===<br />
<br />
A: This is because the triangles on the tops of the pyramids have very high skewnesses which can prevent tet meshing. Consider a quad face with a 10-to-1 aspect ratio. Connect opposite corners to create diagonals. This is the "top view" of the pyramid that would be created on this face. The triangles are very highly skewed. It is recommended that your quad faces bounding a region to be tet-meshed have aspect ratios of 5-to-1 or lower.<br />
<br />
===Q: I'm trying to mesh a geometry but I'm getting this message: “check the skewnesses of you face meshes and make sure the face mesh sizes are not too large in areas of small gaps.” I checked the skewness and it's low enough. ===<br />
<br />
A: Your problem is most likely that you have small gaps where the local surface mesh sizes are much larger than the gap sizes. Refining the surface meshes in those areas is likely to solve the problem.<br />
<br />
===Q: I would like to generate grids for different zones using Gambit. How do I merge them together using Gambit or Tgrid later?===<br />
<br />
A: For a valid conformal mesh, mesh nodes on the faces at the interface of the two parts have to be matching within a tolerance. Then, you can either merge the nodes (using Tgrid) or fuse the zones (using Fluent). If you use Tgrid to merge the duplicate nodes, the resulting surface at the interface will have the boundary type as "wall" which should be changed to "interior" if both sides of the interface have same cell (fluid) zone. Fluent automatically converts the resulting surface after fuse to be of "interior" type if both sides of it has the same cell (fluid) zone. <br />
<br />
Also, if you are not using Tgrid, you need to use tfilter tmerge3d to merge the meshes together before reading them into Fluent. Tgrid does the same when you load multiple mesh files at a time. <br />
<br />
===Q: How do I determine what kind of grid to generate? (I would like to known selection criteria between structured and unstructured mesh.)===<br />
<br />
A: Try this approach - consider the meshing options in this order: Single-Block Structured, Multi-Block Structured, Multi-Block Hybrid/Mixed, Fully Unstructured. Gambit can generate most of the cells types and topologies that Fluent can use (with the notable exception of nonconformal meshes). Here are some guidelines/suggestions:<br />
* If you can generate a single-block structured mesh for your problem, then stop there. There is no need to go further. <br />
* If your solution is having problem around a corner (or the like), try multi-block structured mesh. If you are getting improved solution, then stop there. <br />
* If you still have problems around different part of the corner, try the unstructured mesh, with high density mesh around the corner. Before going to a fully unstructured mesh, try making only the problem region unstructured. If the solution is good, then stop there. <br />
* If one part of the mesh still requires special attention, then you can use Fluent's adaptive unstructured facility to refine the mesh until the solution is acceptable. Ideally, you should still get a mesh independent solution. <br />
* It is very important to be able to control every part of your mesh so that you can get good solution everywhere. This is more difficult with unstructured meshes. <br />
* For many geometries, if you can use a structured mesh you will end up with fewer cells (this is particularly true in three dimensions). It is a good idea to use structured-type meshes in regions that will allow it, and use unstructured meshes everywhere else.<br />
* Don't forget that Fluent can handle prismatic cells. If you have an unstructured surface mesh, Gambit can generate a layer of prismatic cells that will resolve boundary layers without requiring a (fully) structured mesh.<br />
<br />
===Q: How do I run GAMBIT as a batch process?=== <br />
<br />
A: To run Gambit in "batch" mode, prepare a journal file (e.g., "test.jou"), then use the command : gambit test -in test.jou <br />
<br />
=== Q: I am having trouble uniting two volumes, what should I do? ===<br />
<br />
"misclassified graph coedge - probably geometrical problem" <br><br />
-> you can try healing the volumes<br><br />
-> deleting the volume (without lower geometry), healing and uniting the faces, then build the volume again<br />
<br />
===Q: I am trying to move a node to modify the mesh on a face with mouse. Why in y direction I can only move the node discretely by 0.5 or multiples of 0.5? I can move it continuously in x direction and I would like to do so in y as well. Is there some default value to change? ===<br />
<br />
== Other Preprocessing Codes==<br />
=== Gambit Turbo ===<br />
<br />
=== TGrid ===<br />
<br />
== Application specific codes ==<br />
<br />
=== Icepak ===<br />
<br />
=== Airpak ===<br />
<br />
=== MixSim ===<br />
<br />
== Educational codes ==<br />
<br />
=== FlowLab ===<br />
[http://flowlab.fluent.com]<br />
<br />
[[Category: FAQ's]]<br />
<br />
{{stub}}</div>Jasondhttp://www.cfd-online.com/Wiki/Fluent_FAQFluent FAQ2007-08-23T18:09:50Z<p>Jasond: Added a section for post-processing questions</p>
<hr />
<div>This article contains questions and answers on the use of Fluent products (mainly Fluent and Gambit). Please feel free to add questions and answers here!<br />
<br />
== General Information ==<br />
<br />
=== What is Fluent? ===<br />
There are two answers to this question: Fluent (the company) is a CFD software company that is now part of ANSYS Inc. Fluent (the software package) is a popular commercial CFD package.<br />
<br />
=== What is Gambit? ===<br />
Gambit is a meshing software package that is typically purchased{{Fact}} with Fluent.<br />
<br />
=== How can I learn Fluent and Gambit? ===<br />
<br />
The documentation provided by Fluent is actually quite good, so it is a very good place to start. Fluent also provides tutorials and documentation<br />
on the [http://www.fluentusers.com fluentusers] site, which is open to everyone with a<br />
(full) license. Without a full commercial license, it is possible to use the tutorials given at [http://www.studentfluent.com/ studentfluent], or you may be able to register to use the user services center through other channels (e.g. through the university program). There are also some good tutorials available at [http://instruct1.cit.cornell.edu/courses/fluent/index.htm Cornell] and at various other places on the web (Google is a good place to start).<br />
<br />
=== Using CFD-Online's Fluent Forum ===<br />
<br />
==== How should I ask my question on the Fluent forum to get the most useful answer? ====<br />
<br />
It is important to understand that the quality of the answer to your question depends upon how well you ask your question. Many of the questions posted on the Fluent forum are so poorly posed that it is very difficult to understand what the poster is actually asking. Here are some suggestions to avoid this problem:<br />
<br />
# Make sure your question is as clear, concise, and as specific as possible. Other forum readers are unlikely to spend time trying to decipher a garbled question.<br />
# Give a clear general description of what class of problem and/or application you are working on before you start asking specific questions. This will aid other forum readers to better understand your specific questions.<br />
# Describe precisely what you have done yourself to try and solve your problem, giving examples.<br />
# Depending on your problem, you should try to include the following:<br />
#*If you are asking a mesh quality related question then include some sample images of your mesh, including the boundary layer.<br />
#*If you are asking a UDF question then include a copy of your existing code file as an attachment or in your post using <nowiki><pre></nowiki> tags to keep the code legible.<br />
<br />
==== How do I upload images? ==== <br />
* Create the image on your local machine e.g. skew_mesh.jpg<br />
* Upload the image to [http://www.imageshack.us Imageshack]<br />
* Copy the link "Thumbnail for websites"<br />
* Paste the link into your post e.g. <i><nowiki><a href="http://img91.imageshack.us/my.php?image=pipeym8.jpg" target="_blank"><img src="http://img91.imageshack.us/img91/5681/pipeym8.th.jpg" border="0" alt="Free Image Hosting at www.ImageShack.us" /></a></nowiki></i><br />
<br />
==== How do I share non-image files as attachments? ====<br />
* If you have more than one file, zip them into a single file.<br />
* Upload the file to [http://www.rapidshare.de Rapidshare] [http://www.gigasize.com/ Gigasize]<br />
* Scroll down to "I don't want a collector's account right now. Just give me the download-link." and click it.<br />
* Scroll down until you see the link e.g. <i><nowiki>http://rapidshare.de/files/33808646/audio.log.html</nowiki></i><br />
<br />
== FLUENT ==<br />
=== Solver Related ===<br />
==== What does "floating point error" mean? How can I avoid it? ====<br />
<br />
The floating point error has been reported many times and discussed a lot. Here are some of the answers found in the Fluent Forum:<br />
<br />
From numerical computation view point , the basic operations performed by computer are represented inside computer in what is called floating point numbers. The errors that are either because of invalid numeric computation initiated by user or limitation of machine that is used are floating point errors.<br />
<br />
1)Invalid Operations:- Simplest example is if one uses Newton Raphson root finding method to solve f(x)=0 and for some Nth iteration if we get x = x(N) such that derivative of function f(x), f'(x(N))=0 then formula for calculating next iterate x(N+1) = x(N) - f(x(N))/f'(x(N)) requires division by f'(x(N)) which is zero. Here you get divide by zero type of floating point error.<br />
<br />
2) Over or Underflow:- Another type is having data with either too large or too small magnitude called 'overflow' or 'underflow' respectively.Such data cannot be physically represented on computer for direct processing by arithmetic processing part of Processor. <br />
<br />
3) Rounding off errors :- While rounding off a decimal number , some significant digits are lost which cannot be recovered .<br />
e.g. if we round off 0.1 to integer (not greater than it called 'floor' of the given no.) then it is zero. If this value if further used for computation then it may lead to several errors.<br />
<br />
'''SOLVER AND ITERATION''' -----I think if you set shorter time step, it may be good. Or changing little Under-Relaxiation-Factors, it may be good. In my experience, I set 1/3 Under-Relaxiation-Factors as default.� -----�also lower the values of under relaxation factor and use the coupled implicit solver� -----�Try to change under-relaxation factors and if it is unsteady problem maybe time step is to large.� -----�you can improve the ratio in the solve--control--limits, maybe that can help.� -----�you will need to decrease the Courant number� -----�If you still get the error, initialize the domain with nothing to 'Compute from...' Then click 'init'. Again select the surface from which you want to compute the initial values & iterate. This should work.� -----�Another reason could be a to high courant number - that means, that the steps between two iterations are too large and the change in the results is too large as well (high residuals)�<br />
<br />
'''GRID PROBLEMS''' -----�this error comes when I start scaling grid. in gambit, all my dimension is in mm, when in fluent i convert it in meter using buttone SCALE. after it, when i iterate, about hundred iteration, this error appeared. but when i not scale my drawing to m...and let it be as in gambit..then the iteration is success. -----�hi I think you should check your mesh grid mesh is very high. your problem solve by selection a low mesh.� -----�Your mesh is so heavy that your computers resources are not enough. try to use coarser mesh.�<br />
<br />
'''BOUNDARY CONDITIONS''' -----�In my case I had set a wall boundary condition instead of an axis boundary condition and then FLuent refuses to calculate telling me 'floating point error'.� -----�Your Boudary Conditions do not represent real physis.� -----�wrong boundary condition definition might cause the floating point error. For example setting an internal boundary as interior� -----�Once I had the problem, simulating a 2D chamber with a symmetry BC. I set the symmetry somewhere as �axe symmetric� and the floating point error occur� -----�check the turbulence parameter you set. reduce the turbulence intensity to less that one for first, say 50 iterations.<br />
<br />
'''MULTI PROCESSOR ISSUES''' -----"I've had similar problems recently with floating point errors on a multi processor simulation. The solution for my problem seems to be to run on a single processor, where it runs fine....?�<br />
<br />
'''WRONG INITIATION''' ----- Initiating the case with wrong conditions may lead to floating point error when the iterations start.<br />
<br />
==== What is the difference between the coupled and the segregated solver? ====<br />
In the latest Fluent release,6.3.26 these are referred as density based and pressure based solvers.<br />
<br />
The coupled solver will solve all equations (conservation equations for mass, momentum and energy) simultaneously instead of sequentially (the equations are segregated from one another). You should use the coupled solver when the velocity and pressure are strongly coupled (high pressures and high velocities), but very long calculation times may be required when you use the coupled solver.<br />
<br />
In the coupled solvers, the Species Diffusion Term is always included in the energy equation.<br />
<br />
When you use the segregated solver, FLUENT allows you to specify anisotropic conductivity for solid materials<br />
<br />
From the [http://www.cfd-online.com/Forum/fluent_archive.cgi?read=40127 Fluent forum]:<br />
<br />
Choice of solvers depends heavily on the model being solved. The segregated solver solution is based on the pressure, while the coupled solver solution is based on density. This makes the segregated solver better at low speed flows and the coupled solver better at solving transonic / supersonic cases. I wouldn't recommend the coupled solver at any flows below Mach .4 (until the pressure based coupled solver comes out in the next release of Fluent). I've used the Segregated solver up to Mach 1.5 with great results, but the higher speed, the more mesh dependent you become (because the segregated solver tends to "smooth out" shocks), so you have to pay a lot of attention to your meshing.<br />
<br />
The coupled solver tends to be more stable with the defaults settings. The segregated solver tends to be very sensitive to the allowable limits. When trying to get a solution with the segregated solver, DO NOT increase the turbulent viscosity ratio limit (unless you have a great reason to based on past experience or the physics of your current model truly exceeding that limit, but I've never even heard of that being realistic). Instead limit the pressure and temperature limits to reasonable limits (i.e. Plimits = Pstatic +/- (2 * dynamic pressure), and calculate the appropriate temps). You need to give the solution "room to move" while it reaches a solution, but you don't want to give it enough room where it goes out to some totally impossible numbers, and the limits help prevent this.<br />
<br />
=== Model Related ===<br />
==== What is the turbulent viscosity ratio warning and how can I handle it? ====<br />
The problem can be caused by improper values for the boundary condition turbulence parameters. Check the fluent manual (which is kind of more like a textbook), about modeling turbulence.<br />
<br />
For the case of internal flow, you basically have to consider the physical state of the fluid upon entrance to your control volume. If the fluid is coming into your volume from a fully developed turbulent pipe flow, it will have more turbulent energy than from a stagnant fluid. Think of lots of little vortices, which mostly mix things up, and those all have kinetic energy associated). This energy can be expressed as a nondimensional Intensity (a percentage is used). In addition, a Length parameter is specified.<br />
<br />
==== How can I determine the inputs for a porous media or porous jump from flow versus pressure drop data? ====<br />
If you have pressure drop versus velocity data, you can fit the following equation through the data:<br />
<br />
<math>\Delta P = Av^2 + Bv</math><br />
<br />
where <math>\Delta P</math> is the pressure drop and <math>v</math> is the velocity. The coefficients <math>A</math> and <math>B</math> are related to the Fluent variables for the permeability <math>\alpha</math>, and the pressure coefficient <math>C_2</math> by<br />
<br />
<math>A = \frac{C_2 \rho \Delta n}{2}</math> and <math>B=\frac{\mu}{\alpha}\Delta n</math><br />
<br />
where <math>\Delta n</math> is the thicknes of the medium.<br />
<br />
==== How do I model heat conduction in a composite wall? ====<br />
<br />
==== What pressures should be specified at inlets and outlets for buoyancy flow problems? ====<br />
<br />
what pressures at inlet and outlet should specified in natural convection?<br />
<br />
==== Are there any general guidelines on selecting a turbulence model? ====<br />
<br />
==== How can both turbulent and laminar flow be included in one model? ====<br />
<br />
Depends. Fluent cannot presently compute boundary layer instability and subsequent transition to turbulence using a RANS approach (ke, SST, RSM etc). CFX has a new feature to do this, so perhaps it will be incorporated into Fluent soon as they are both owned by ANSYS.<br />
<br />
You therefore have two options : <br />
<br />
1. If you know the point of transition (like on an aircraft wing) from experimental data or DNS simulations, you can impose laminar flow in some regions by meshing a separate fluid region, and enabling "laminar zone" for this region in boundary settings. That is also useful in heat transfer cases, if for example you have turbulent flow one side of a thermal wall, and natural convection on the other side.<br />
<br />
2. A "near-wall" turbulence approach : Either k-omega, SST, or Low Reynolds k-E (which you have to select from the "Turbulence modelling/expert" menu), will damp turbulence near to the wall, either by empirical damping of turbulent "k" (Low Reynolds k-E) or by full solution of the omega equation on a fine enough mesh (k-omega/SST). If you have flows in small gaps in a larger, turbulent domain, in which large lengthscales of turbulence of course could not be supported, the flow will re-laminarise in a physically sensible (although perhaps not mathematically exact) manner. These models will also MAINTAIN laminar flow in external boundary layers, PROVIDED that you have a fine enough mesh (use the laminar mesh distribution guidelines in Fluent manual, too coarse a mesh will lead to non-physical turbulence generation in the BL). BUT they will maintain this laminar flow and evolution of the laminar profile (in the absence of significant disturbance by separation or impingement at the wall) forever, no spontaneous instability or transition to turbulence will occur. So check the length-based Reynolds numbers of walls where you think there will be undisturbed laminar boundaries, that there is not expected to be spontaneous transition of these BLs.<br />
<br />
==== How to start a 3D simulation with an compressible medium and temperature changes? What is important to consider ====<br />
<br />
<br />
I would do it that way:<br />
<br />
1. solve the flow for incompressible medium, without energy equation. Set the density close to the density, that you expect at the present pressure and temperature. The solution for the flow dosn't has to be completely convergent, but the residuals should be on the way down. <br />
<br />
2. Apply energy equation and compressibility of the gas and set the present pressure with operating condition option. You might do some iteration steps as well. Sometimes they are not necessary<br />
<br />
3. Apply the thermal BC<br />
<br />
=== Solution Methodology === <br />
==== How do I carry out rotating body analysis, eg a rotating sphere or cylinder''' in flo'''w? ====<br />
Rotating cylinder problem ( assume circular ), can be done easily by specifying angular velocity on the cylinder wall. As i observed no need of moving mesh for this case. you need to specify the rotation axis with respect to which your cylinder is rotating.<br />
<br />
==== How do I get better and faster convergence? ====<br />
==== What is the role of under-relaxation parameters? What should be the optimum choice of these parameters? ====<br />
They limit the influence of the previous iteration over the present one. If you choose small values it may prevent oscillations in residuum developing. At the same time the solution may need more time to converge. <br />
Keep the default values as they are given in FLUENT. You can decrease them gradually if necessary. Momentum 0.6, pressure 0.1, k 0.4, eps 0.4, mass source 1, viscosity 1.<br />
<br />
=== User-Defined Function (UDF) Related ===<br />
<br />
==== How do I learn UDF programming? ====<br />
There are not to many tutorials out there on this, probably due to the wide variety of things you can do with the UDF interface. The documentation the Fluent provides is pretty good once you know what you are trying to do (chapter 8 of the UDF manual has examples). UDF programming is easier if you have C programming experience, so it is advisable to learn a little C programming, then do some of the simple cases that Fluent provides, then tackle the problem you really want to solve. <br />
<br />
==== How do I create/build/load a UDF? ====<br />
The simplest way to add a UDF into Fluent is to write your UDF in the C programming language and then use Define -> User-Defined -> Functions to either interpret or compile your UDF. It can then be loaded. Fluent provides good documentation of the UDF interface with numerous examples, so read that before trying too much.<br />
<br />
==== Do I have to use C? ====<br />
Yes and no. To hook your UDF into Fluent, you'll probably have to use one of the DEFINE_* macros that Fluent provides, and this is most easily done using C. However, you can write routines that are used in the routines that are defined with the DEFINE_* macros in other languages and then link them together. This requires some knowledge of mixed language programming, Makefiles, the text user interface (TUI), and is not necessarily very portable. An example using Fortran is given in Section 5.4.1 of the Fluent UDF Manual (version 6.3).<br />
<br />
==== Which compilers work? ====<br />
On Unix-like machines, GCC is the compiler of choice. On Windows machines, Microsoft Visual C++ is the compiler of choice (GCC may also work on Windows- if anyone has firsthand knowledge of this, please share). The free Express Edition of the Microsoft compiler also works.<br />
<br />
==== My UDF won't interpret or compile - what is wrong? ====<br />
The answer depends upon what exactly has happened. <br />
<br />
*If Fluent complains about not being able to find a compiler, then check to make sure that the compiler is properly installed. On Windows machines, it is possible to install the Visual C++ compiler without fully setting up the command line compiler (which Fluent needs to be able to find). During the installation process, you need to select the "register environment variables" option. Failure to do so will likely lead to complaints about things being "not recognized as an internal or external command, operable program or batch file" or missing DLL's. It is theoretically possible to fix this issue by setting the appropriate environment variables, but keep in mind that even when nmake can be found there still may be DLL issues. The easy path is probably reinstallation of Visual Studio (taking special care to make sure that the command line interface is set up properly), but the reinstallation path is always perilous. If you have long-term experience using Windows you should probably know the risks, and if you don't you should consult an expert.<br />
<br />
*If you are interpreting, keep in mind that not everything that is supported for compiled UDF's is supported for interpreted UDF's. This is true both for the UDF interface and the C language. If you are doing something pretty involved and it fails inexplicably, try compiling to see if that makes a difference.<br />
<br />
*There is also the possibility of coding errors. Keep in mind that your source code gets run through the C preprocessor (to change the Fluent macros into C code), so unintended interactions are very possible.<br />
<br />
==== Why do I get the message "'nmake' is not recognized as an internal or external command, operable program or batch file"? ====<br />
This is a Windows/Visual Studio issue. In order to compile your UDF, Fluent needs to know where the nmake program is located, and it currently can't find it. If you open up a command window and enter "nmake", you should probably get the same message. See the previous question/answer.<br />
<br />
==== My UDF interprets/compiles but fails to execute - what is wrong? ====<br />
This commonly occurs due to a faulty operation of some kind. For example, user-defined memory (UDM) is not allocated until initialization, so attempting to access a UDM variable before initialization can lead to a segmentation fault. Try to isolate the cause, and then look for places where your expectation of what is available may not match reality. Finally, keep in mind that if you do something really bad, you may need to restart Fluent before even a fixed UDF will work.<br />
<br />
=== Post-Processing Related ===<br />
<br />
=== Journal File and Text User Interface (TUI) Related ===<br />
==== What is the Text User Interface? ====<br />
The Text User Interface (TUI) is a command-line-like interface to Fluent. The TUI is accessed through the main Fluent (hit enter while in the main Fluent window), with a menu system and the ability to execute Scheme programs. Fluent's documentation compares the menu system to the UNIX directory structure. Since it is text base, you can create and modify sequences of TUI commands using a simple text editor (see journal files below).<br />
<br />
When Fluent starts, you are in the "root" menu: press enter and you'll see something like this:<br />
<pre><br />
><br />
adapt/ file/ report/<br />
define/ grid/ solve/<br />
display/ parallel/ surface/<br />
exit plot/ view/<br />
</pre><br />
To access the plot menu, just type in "plot" and then press enter. To bring up the available commands, press enter again:<br />
<pre><br />
> plot<br />
<br />
/plot> <br />
change-fft-ref-pressure file-set/ residuals<br />
circum-avg-axial flamelet-curves residuals-set/<br />
circum-avg-radial histogram solution<br />
fft histogram-set/ solution-set/<br />
file plot<br />
file-list plot-direction<br />
</pre><br />
<br />
To exit a menu, simply type "q" and press enter (the rough equivalent of "cd .." in Unix). The TUI also understands command abreviations, so "pl/rs" is interpreted as "plot/residuals-set".<br />
<br />
==== What is a journal file? ====<br />
A journal file is a series of TUI commands stored in a text file. The file can be written in a text editor or generated by Fluent as a transcript of the commands given to Fluent during your session. A journal file generated by Fluent will include any GUI operations (in a TUI form, though). This is quite useful if you have a series of tasks that you need to execute, as it provides a shortcut. To record a journal file, start recording with File -> Write -> Start Journal..., perform whatever tasks you need, and then stop recording with File -> Write -> Stop Journal...<br />
<br />
==== How do I add a comment in a journal file? ====<br />
Any line beginning with a ''';''' (semicolon) is treated as a comment.<br />
<br />
==== How do I set boundary conditions? ====<br />
Suppose we have a boundary named "south" that we want to set as a wall. The command is<br />
<pre><br />
/define/boundary-conditions/zone-type south wall<br />
</pre><br />
which sets the zone "south" as a wall. The details (moving wall, etc.) can then be accessed be executing<br />
<pre><br />
/define/boundary-conditions/wall south<br />
</pre><br />
in the text user interface.<br />
<br />
==== How do I write a XY-plot? ====<br />
look at<br />
http://www.cfd-online.com/Forum/fluent_archive.cgi?read=40200<br />
<br />
==== How do I set material properties? ====<br />
look at http://www.cfd-online.com/Forum/fluent_archive.cgi?read=38768<br />
<br />
one example:<br />
<br />
<pre><br />
//define/materials/delete<br />
air_50c<br />
//define/materials/delete<br />
air_1bar<br />
//define/materials/change-create<br />
air<br />
air_1bar<br />
y<br />
incompressible-ideal-gas<br />
y<br />
piecewise-linear<br />
2<br />
298.15<br />
1007<br />
323.15<br />
1008<br />
y<br />
piecewise-linear<br />
2<br />
298.15<br />
0.02606<br />
323.15<br />
0.02788<br />
y<br />
piecewise-linear<br />
2<br />
273.15<br />
1.72E-05<br />
433.15<br />
2.45E-05<br />
n<br />
n<br />
n<br />
n<br />
n<br />
n<br />
y<br />
</pre><br />
<br />
==== How do I generate a hardcopy of a window? ====<br />
<br />
<pre><br />
display set-window 1 ; if window nr. 1 is the window you want to be hardcopied<br />
//display/set/windows/scale/form ; setting the options for the graph (colourmap)<br />
"%0.2f"<br />
//display/set/color-ramp<br />
bgr<br />
//display/set/hardcopy/color ; setting the options for the window<<br />
color<br />
//display/set/hardcopy/driver<br />
tiff<br />
//display/set/hardcopy/y-res<br />
2400<br />
//display/set/hardcopy/x-res<br />
3106<br />
//display/set/hardcopy/inv<br />
no<br />
//display/hard<br />
filename.tiff<br />
//display/set/hardcopy/inv<br />
yes<br />
//display/hard<br />
filename_inv.tiff<br />
</pre><br />
<br />
==== How do I run multiple cases in batch mode? ====<br />
This could be achieved by running it from journal file. The example journal file that runs two cases is given as:<br />
<pre><br />
file read-case-data xxx1.cas<br />
solve dual-time-iterate yyy1<br />
file write-case-data zzz1.cas<br />
file read-case-data xxx2.cas<br />
yes ; for discard cas dialog<br />
solve dual-time-iterate yyy2<br />
file write-case-data zzz2.cas<br />
</pre><br />
<br />
<br />
Another example:<br />
<pre><br />
rcd filemname.cas<br />
yes<br />
it 10000 <br />
wcd filemname.cas <br />
yes<br />
</pre><br />
<br />
<br />
Have a look at this discussion: [http://www.cfd-online.com/Forum/fluent_archive_2005.cgi/read/32615 http://www.cfd-online.com/Forum/fluent_archive_2005.cgi/read/32615]<br />
<br />
==== How do I loop in a journal file? ====<br />
The best way to loop in a journal file (or the text user interface) is to use one of the Scheme programming language's looping constructs.<br />
<br />
=== Tips === <br />
==== How do I merge two mesh files into one mesh file? ====<br />
To merge two mesh files the suggested utility is tmerge. The syntax of tmerge is simple.<br><br />
<i>utility tmerge -3d file1 file2 finalfile </i> <br><br />
To join the two interior faces use: <br><br />
<i>Grid->Fuse</i> <br><br />
from the menu with Fluent.<br />
<br />
==== How do I export Fieldview data for postprocessing during iterations? ====<br />
<br />
This could be done with the help of menu <b>solve->Execute Commands </b>. <br />
Here are two examples:<br />
<br />
'''Steady Case'''<br />
<br />
<pre><br />
file/export/fug/File_grid-%n<br />
file/export/fud/File_data-%n pressure velocity-magnitude x-velocity y-velocity z-velocity () </pre><br />
<br />
'''Unsteady Case'''<br />
<br />
<pre><br />
file/export/fug/File_grid-%t<br />
file/export/fud/File_data-%t pressure velocity-magnitude x-velocity y-velocity z-velocity () </pre><br />
<br />
You can chose the frequency of export from the <b>Execute Command</b> panel.<br />
<br />
==== What does abbreviation X mean?====<br />
<br />
{| border="1"<br />
|- <br />
| APG || adverse pressure gradient<br />
|- <br />
| BC || Boundary Conditions<br />
|- <br />
| B-L || Boundary Layer<br />
|-<br />
| CFD || Computational Fluid Dynamics<br />
|-<br />
| DES || Detached Eddy Simulation<br />
|-<br />
| DPM || Discrete Phase Model<br />
|-<br />
| FDM || Finite Difference Method<br />
|-<br />
| FEM || Finite Element Method<br />
|-<br />
| FVM || Finite Volume Method<br />
|-<br />
| GUI || Graphical User Interface<br />
|-<br />
| LES || Large Eddy Simulation<br />
|-<br />
| MUSCL || Monotone Upstream-centered Scheme for Conservation Laws<br />
|-<br />
| MDM || Moving and Deforming Mesh<br />
|-<br />
| PDF || Probability Density Function<br />
|-<br />
| QUICK || Quadratic Upstream Interpolation for Convective Kinematics<br />
|-<br />
| RANS || Reynolds Averaged Navier-Stokes<br />
|-<br />
| RSM || Reynolds Stress Model<br />
|-<br />
| SIMPLE || Semi-Implicit Method for the Pressure-Linked Equation<br />
|-<br />
| SST || Shear Stress Transport<br />
|-<br />
| TUI || Text User Interface<br />
|-<br />
| UDF || User defined function<br />
|-<br />
| URF || Under Relaxation Factor<br />
|-<br />
| VOF || Volume Of Fluid<br />
|}<br />
<br />
==== What is the difference between FE and FV?====<br />
<br />
See the answer in the [[General CFD FAQ#What is the difference between FEM, FVM and FDM?|General CFD FAQ]].<br />
<br />
== FloWizard==<br />
<br />
== FIDAP==<br />
<br />
== POLYFLOW ==<br />
<br />
== Gambit ==<br />
===Why does Gambit refuse to open my .dbs file and say that my file is already open? I get an error message - ERROR: IDENTIFIER "X" CURRENTLY OPEN.===<br />
Before opening your file "X.dbs", Gambit looks for a file named "X.lok" to determine the status of your file. If it finds the .lok file, you'll get the above error message (or something like it). If you are in a multi-user environment, you should check that it is not actually already open elsewhere, but in other situations the most likely reason that there is still a X.lok file is that Gambit encountered a problem the last time X.dbs was open. Deleting the .lok file should solve your problem.<br />
<br />
===Q: Why does Gambit complain about the number of nodes on edges being odd and then refuse to mesh a face?===<br />
<br />
A: It is mathematically impossible to create an all-quad mesh with an odd number of intervals on the outer edge loop. If this is inconvenient for you, you may consider a quad-dominant mesh (mostly quads, with a few triangles), or even an all-triangle mesh. Many users achieved good solutions with triangle surface meshes and prism (wedge) boundary layers.<br />
<br />
===Q: What are these boundary layers things defined in Gambit? Do they represent the real situation?===<br />
<br />
A: Gambit's boundary layers allow you to generate specific semi-structured grids topologies on faces that grow out from an edge or edges. You can specify the initial cell height, the growth rate, and a transition pattern that changes the edge-parallel interval count. There are several default settings, which can affect the quality of boundary layers. For cases with sharp corners, normal and offset smoothing can greatly improve quality. Such smoothing is off by default because it requires significantly more computation time.<br />
<br />
===Q: If my quad face mesh has cells with high skewness or large aspect ratios, the pyramiding procedure used by the tet mesher will frequently lead to failure, why? ===<br />
<br />
A: This is because the triangles on the tops of the pyramids have very high skewnesses which can prevent tet meshing. Consider a quad face with a 10-to-1 aspect ratio. Connect opposite corners to create diagonals. This is the "top view" of the pyramid that would be created on this face. The triangles are very highly skewed. It is recommended that your quad faces bounding a region to be tet-meshed have aspect ratios of 5-to-1 or lower.<br />
<br />
===Q: I'm trying to mesh a geometry but I'm getting this message: “check the skewnesses of you face meshes and make sure the face mesh sizes are not too large in areas of small gaps.” I checked the skewness and it's low enough. ===<br />
<br />
A: Your problem is most likely that you have small gaps where the local surface mesh sizes are much larger than the gap sizes. Refining the surface meshes in those areas is likely to solve the problem.<br />
<br />
===Q: I would like to generate grids for different zones using Gambit. How do I merge them together using Gambit or Tgrid later?===<br />
<br />
A: For a valid conformal mesh, mesh nodes on the faces at the interface of the two parts have to be matching within a tolerance. Then, you can either merge the nodes (using Tgrid) or fuse the zones (using Fluent). If you use Tgrid to merge the duplicate nodes, the resulting surface at the interface will have the boundary type as "wall" which should be changed to "interior" if both sides of the interface have same cell (fluid) zone. Fluent automatically converts the resulting surface after fuse to be of "interior" type if both sides of it has the same cell (fluid) zone. <br />
<br />
Also, if you are not using Tgrid, you need to use tfilter tmerge3d to merge the meshes together before reading them into Fluent. Tgrid does the same when you load multiple mesh files at a time. <br />
<br />
===Q: How do I determine what kind of grid to generate? (I would like to known selection criteria between structured and unstructured mesh.)===<br />
<br />
A: Try this approach - consider the meshing options in this order: Single-Block Structured, Multi-Block Structured, Multi-Block Hybrid/Mixed, Fully Unstructured. Gambit can generate most of the cells types and topologies that Fluent can use (with the notable exception of nonconformal meshes). Here are some guidelines/suggestions:<br />
* If you can generate a single-block structured mesh for your problem, then stop there. There is no need to go further. <br />
* If your solution is having problem around a corner (or the like), try multi-block structured mesh. If you are getting improved solution, then stop there. <br />
* If you still have problems around different part of the corner, try the unstructured mesh, with high density mesh around the corner. Before going to a fully unstructured mesh, try making only the problem region unstructured. If the solution is good, then stop there. <br />
* If one part of the mesh still requires special attention, then you can use Fluent's adaptive unstructured facility to refine the mesh until the solution is acceptable. Ideally, you should still get a mesh independent solution. <br />
* It is very important to be able to control every part of your mesh so that you can get good solution everywhere. This is more difficult with unstructured meshes. <br />
* For many geometries, if you can use a structured mesh you will end up with fewer cells (this is particularly true in three dimensions). It is a good idea to use structured-type meshes in regions that will allow it, and use unstructured meshes everywhere else.<br />
* Don't forget that Fluent can handle prismatic cells. If you have an unstructured surface mesh, Gambit can generate a layer of prismatic cells that will resolve boundary layers without requiring a (fully) structured mesh.<br />
<br />
===Q: How do I run GAMBIT as a batch process?=== <br />
<br />
A: To run Gambit in "batch" mode, prepare a journal file (e.g., "test.jou"), then use the command : gambit test -in test.jou <br />
<br />
=== Q: I am having trouble uniting two volumes, what should I do? ===<br />
<br />
"misclassified graph coedge - probably geometrical problem" <br><br />
-> you can try healing the volumes<br><br />
-> deleting the volume (without lower geometry), healing and uniting the faces, then build the volume again<br />
<br />
===Q: I am trying to move a node to modify the mesh on a face with mouse. Why in y direction I can only move the node discretely by 0.5 or multiples of 0.5? I can move it continuously in x direction and I would like to do so in y as well. Is there some default value to change? ===<br />
<br />
== Other Preprocessing Codes==<br />
=== Gambit Turbo ===<br />
<br />
=== TGrid ===<br />
<br />
== Application specific codes ==<br />
<br />
=== Icepak ===<br />
<br />
=== Airpak ===<br />
<br />
=== MixSim ===<br />
<br />
== Educational codes ==<br />
<br />
=== FlowLab ===<br />
[http://flowlab.fluent.com]<br />
<br />
[[Category: FAQ's]]<br />
<br />
{{stub}}</div>Jasondhttp://www.cfd-online.com/Wiki/Talk:Ansys_FAQTalk:Ansys FAQ2007-08-22T02:24:02Z<p>Jasond: /* Discussion regarding "Ansys FAQ" */</p>
<hr />
<div>== Discussion regarding "Ansys FAQ" ==<br />
Hi,<br />
<br />
I really dislike this entry. I don't feel that it is in accordance with ''any'' of the [[CFD-Wiki:Policy ]] community guidelines, for instance it is not NPOV, I cannot verify it (no references or citations are provided) and I have no idea whether ANSYS may consider this information proprietary. <br />
<br />
I think that, at best it should be zoned to a forum of it's own and removed from the educational resource that is CFD-Wiki.<br />
<br />
Any opinions appreciated!<br />
<br />
--[[User:Roberthealy1|Roberthealy1]] 16:42, 21 August 2007 (MDT)<br />
<br />
: What do you mean by "entry"? Do you mean the entire thing, or parts of it? It probably could be renamed as a CFX FAQ, but that would not address the other issue that you raise about being able to verify it. I'm not sure that the normal rules on such things apply in this particular instance. For example, there are things in the [[Fluent FAQ]] that cannot be verified in any real sense because the features are essentially undocumented. It is explicitly associated with the Fluent forum, but that doesn't change the fact that the (good) point you raise applies there, too. On the propietary issue: I don't think they would claim it as long as it hasn't been copied from their materials.--[[User:Jasond|Jasond]] 20:24, 21 August 2007 (MDT)</div>Jasondhttp://www.cfd-online.com/Wiki/Low-Re_k-epsilon_modelsLow-Re k-epsilon models2007-08-18T15:22:33Z<p>Jasond: </p>
<hr />
<div>{{Turbulence modeling}}<br />
==Introduction==<br />
<br />
Good reviews of classical Low-Re k-epsilon models can be found in [[#References|[Patel (1995)]]] and [[#References|[Rodi (1993)]]]. There are hundreds of different low-Re k-epsilon models in the literature. This article tries to summarize and describe the most common and classical models. Feel free to add more models here, but please only add models that have gained a widespread use in the CFD community.<br />
<br />
==Overview of models==<br />
<br />
The models presented presented here are:<br />
<br />
{| cellpadding="5" cellspacing="0" border="1"<br />
|-<br />
|'''Model''' || '''Reference''' || '''Description'''<br />
|- <br />
|nowrap|Chien Model ||nowrap| [[#References|[Chien (1982}]]] || A very common model in turbomachinery applications. Has nice numerical properties.<br />
|-<br />
|nowrap|Launder-Sharma Model ||nowrap| [[#References|[Launder (1974)]]] || An old classical model which has attracted some attention for its ability to in model cases predict by-pass transition.<br />
|-<br />
|nowrap|Nagano-Tagawa Model ||nowrap|[[#References|[Nagano (1990)]]] || A model originally developed for heat-transfer applications.<br />
|}<br />
<br />
==Governing equations==<br />
<br />
These models can be written in a general form like:<br />
<br />
:<math><br />
\frac{\partial}{\partial t} \left( \rho k \right) +<br />
\frac{\partial}{\partial x_j} <br />
\left[<br />
\rho k u_j - \left( \mu + \frac{\mu_t}{\sigma_k} \right) <br />
\frac{\partial k}{\partial x_j}<br />
\right]<br />
=<br />
P - \rho \epsilon - \rho D<br />
</math><br />
<br />
:<math><br />
\frac{\partial}{\partial t} \left( \rho \epsilon \right) +<br />
\frac{\partial}{\partial x_j} <br />
\left[<br />
\rho \epsilon u_j - \left( \mu + \frac{\mu_t}{\sigma_\epsilon} \right) <br />
\frac{\partial \epsilon}{\partial x_j}<br />
\right]<br />
=<br />
\left( C_{\epsilon_1} f_1 P - C_{\epsilon_2} f_2 \rho \epsilon \right)<br />
\frac{\epsilon}{k}<br />
+ \rho E<br />
</math><br />
<br />
:<math><br />
\mu_t = C_\mu f_\mu \rho \frac{k^2}{\epsilon}<br />
</math><br />
<br />
:<math><br />
P = \tau_{ij}^{turb} \frac{\partial u_i}{\partial x_j}<br />
</math><br />
<br />
Where <math>C_{\epsilon_1}</math>, <math>C_{\epsilon_2}</math>, <math>C_\mu</math>, <math>\sigma_k</math> and <math>\sigma_\epsilon</math> are model constants. The damping functions <math>f_\mu</math>, <math>f_1</math> and <math>f_2</math> and the extra source terms <math>D</math> and <math>E</math> are only active close to solid walls and makes it possible to solve <math>k</math> and <math>\epsilon</math> down to the viscous sublayer. Table below summarizes the constants, damping functions and boundary conditions for all k-epsilon models presented here.<br />
<br />
==Model constants, daming functions and boundary conditions==<br />
<br />
{| cellpadding="5" cellspacing="0" border="1"<br />
|- <br />
|||'''Chien''' || '''Launder-Sharma''' || '''Nagano-Tagawa'''<br />
|-<br />
|<math>c_\mu</math> || <math>0.09</math> || <math>0.09</math> || <math>0.09</math><br />
|-<br />
|<math>\sigma_k</math> || <math>1</math> || <math>1</math> || <math>1.4</math><br />
|-<br />
|<math>\sigma_\epsilon</math> || <math>1.3</math> || <math>1.3</math> || <math>1.3</math><br />
|-<br />
|<math>D</math> || <math>2\, \nu \, \frac{k}{y^2}</math> || <math>2 \, \nu \, \left( \frac{\partial \sqrt{k}}{\partial y} \right)^2</math> || <math>0</math><br />
|-<br />
|<math>E</math> || <math>-\frac{2 \nu \epsilon}{y^2} \exp{-0.5y^+}</math> || <math>2 \, \nu \, \nu_t \, \left(\frac{\partial^2 u}{\partial y^2}\right)^2</math> || <math>0</math><br />
|-<br />
|<math>\epsilon_{wall}</math> || <math>0</math> || <math>0</math> || <math>\nu \, \left( \frac{\partial \sqrt{k}}{\partial y} \right)^2</math><br />
|-<br />
|<math>C_{\epsilon_1}</math> || <math>1.35</math> || <math>1.44</math> || <math>1.45</math><br />
|-<br />
|<math>C_{\epsilon_2}</math> || <math>1.8</math> || <math>1.92</math> || <math>1.9</math><br />
|-<br />
|<math>f_\mu</math> || <math>1-\exp{-0.0115 y^+}</math> || <math> \exp{\frac{-3.4}{\left( 1 + R_t/50 \right)^2}}</math> A || <math>\left(1-\exp{\frac{-y^+}{26}}\right)^2 \left(1+\frac{4.1}{Re_t^{3/4}}\right)</math><br />
|-<br />
|<math>f_1</math> || <math>1</math> || <math>1</math> || <math>1</math><br />
|-<br />
|<math>f_2</math> || <math>1-0.22 \exp{-\left(\frac{Re_t}{6}\right)^2}</math> || <math>1-0.3 \exp{-Re_t^2}</math> || <math>\left(1\!-\!0.3\exp{-\left(\frac{Re_t}{6.5}\right)^2}\right)\!\! \left(1\!-\!\exp{\frac{-y^+}{6}}\right)^2</math><br />
|}<br />
Where <math>Re_t \equiv \frac{k^2}{\nu \epsilon}</math>, <math>y^+ \equiv \frac{u^*y}{\nu}</math> and <math>k_{wall} = 0</math>.<br />
<br />
A According to P. Gardin, M.Brunet, J.F.Domgin and K. Pericleous, "An experimental and numerical CFD study of turbulence in a tundish container", 2nd International Conference on CFD, CSIRO, 1999. There are three options for <math>f_\mu</math><br />
<br />
<br />
D1<br />
<br />
<math> \min \left( 1.0 , \frac{R_t^{1/3}}{45} \right)</math><br />
<br />
<br />
D2<br />
<br />
<math> 1 - \exp{\frac{-R_t}{ 30.1862 }}</math><br />
<br />
<br />
D3<br />
<br />
<math> \exp{\frac{-3.4}{\left( 1 + R_t/50 \right)^2}}</math><br />
<br />
==Performance, applicability and limitations==<br />
<br />
''Not written yet''<br />
<br />
==Implementation issues==<br />
<br />
''Not written yet''<br />
<br />
==References==<br />
<br />
{{reference-paper|author=Chien, K.-Y.|year=1982|title=Predictions of Channel and Boundary-Layer Flows with a Low-Reynolds Number Turbulence Model|rest=AIAA Journal, Vol. 20, No. 1, pp. 33-38}}<br />
<br />
{{reference-paper|author=Nagano, Y. and Tagawa, M.|year=1990|title=An Improved k-epsilon Model for Boundary Layer Flows|rest=Journal of Fluids Engineering, Vol. 112, pp. 33-39}}<br />
<br />
{{reference-paper|author=Patel, V. C. and Rodi, W. and Scheuerer, G.|year=1985|title=Turbulence Models for Near-Wall and Low Reynolds Number Flows: A Review|rest=AIAA Journal, Vol. 23, No. 9, pp. 1308-1319}} <br />
<br />
{{reference-paper|author=Rodi, W. and Mansour, N. N.|year=1993|title=Low Reynolds Number k-epsilon Modeling with the Aid of Direct Simulation Data|rest=Journal of Fluid Mechanics, Vol. 250, pp. 509-529}}<br />
<br />
{{reference-paper|author=Launder, B. E. and Sharma, B. I.|year=1974|title=Application of the Energy-Dissipation Model of Turbulence to the Calculation of Flow Near a Spinning Disc|rest=Letters in Heat and Mass Transfer, Vol. 1, No. 2, pp. 131-138}}<br />
<br />
[[Category:Turbulence models]]</div>Jasondhttp://www.cfd-online.com/Wiki/Low-Re_k-epsilon_modelsLow-Re k-epsilon models2007-08-18T15:20:43Z<p>Jasond: </p>
<hr />
<div>{{Turbulence modeling}}<br />
==Introduction==<br />
<br />
Good reviews of classical Low-Re k-epsilon models can be found in [[#References|[Patel (1995)]]] and [[#References|[Rodi (1993)]]]. There are hundreds of different low-Re k-epsilon models in the literature. This article tries to summarize and describe the most common and classical models. Feel free to add more models here, but please only add models that have gained a widespread use in the CFD community.<br />
<br />
==Overview of models==<br />
<br />
The models presented presented here are:<br />
<br />
{| cellpadding="5" cellspacing="0" border="1"<br />
|-<br />
|'''Model''' || '''Reference''' || '''Description'''<br />
|- <br />
|nowrap|Chien Model ||nowrap| [[#References|[Chien (1982}]]] || A very common model in turbomachinery applications. Has nice numerical properties.<br />
|-<br />
|nowrap|Launder-Sharma Model ||nowrap| [[#References|[Launder (1974)]]] || An old classical model which has attracted some attention for its ability to in model cases predict by-pass transition.<br />
|-<br />
|nowrap|Nagano-Tagawa Model ||nowrap|[[#References|[Nagano (1990)]]] || A model originally developed for heat-transfer applications.<br />
|}<br />
<br />
==Governing equations==<br />
<br />
These models can be written in a general form like:<br />
<br />
:<math><br />
\frac{\partial}{\partial t} \left( \rho k \right) +<br />
\frac{\partial}{\partial x_j} <br />
\left[<br />
\rho k u_j - \left( \mu + \frac{\mu_t}{\sigma_k} \right) <br />
\frac{\partial k}{\partial x_j}<br />
\right]<br />
=<br />
P - \rho \epsilon - \rho D<br />
</math><br />
<br />
:<math><br />
\frac{\partial}{\partial t} \left( \rho \epsilon \right) +<br />
\frac{\partial}{\partial x_j} <br />
\left[<br />
\rho \epsilon u_j - \left( \mu + \frac{\mu_t}{\sigma_\epsilon} \right) <br />
\frac{\partial \epsilon}{\partial x_j}<br />
\right]<br />
=<br />
\left( C_{\epsilon_1} f_1 P - C_{\epsilon_2} f_2 \rho \epsilon \right)<br />
\frac{\epsilon}{k}<br />
+ \rho E<br />
</math><br />
<br />
:<math><br />
\mu_t = C_\mu f_\mu \rho \frac{k^2}{\epsilon}<br />
</math><br />
<br />
:<math><br />
P = \tau_{ij}^{turb} \frac{\partial u_i}{\partial x_j}<br />
</math><br />
<br />
Where <math>C_{\epsilon_1}</math>, <math>C_{\epsilon_2}</math>, <math>C_\mu</math>, <math>\sigma_k</math> and <math>\sigma_\epsilon</math> are model constants. The damping functions <math>f_\mu</math>, <math>f_1</math> and <math>f_2</math> and the extra source terms <math>D</math> and <math>E</math> are only active close to solid walls and makes it possible to solve <math>k</math> and <math>\epsilon</math> down to the viscous sublayer. Table below summarizes the constants, damping functions and boundary conditions for all k-epsilon models presented here.<br />
<br />
==Model constants, daming functions and boundary conditions==<br />
<br />
{| cellpadding="5" cellspacing="0" border="1"<br />
|- <br />
|||'''Chien''' || '''Launder-Sharma''' || '''Nagano-Tagawa'''<br />
|-<br />
|<math>c_\mu</math> || <math>0.09</math> || <math>0.09</math> || <math>0.09</math><br />
|-<br />
|<math>\sigma_k</math> || <math>1</math> || <math>1</math> || <math>1.4</math><br />
|-<br />
|<math>\sigma_\epsilon</math> || <math>1.3</math> || <math>1.3</math> || <math>1.3</math><br />
|-<br />
|<math>D</math> || <math>2\, \nu \, \frac{k}{y^2}</math> || <math>2 \, \nu \, \left( \frac{\partial \sqrt{k}}{\partial y} \right)^2</math> || <math>0</math><br />
|-<br />
|<math>E</math> || <math>-\frac{2 \nu \epsilon}{y^2} \exp{-0.5y^+}</math> || <math>2 \, \nu \, \nu_t \, \left(\frac{\partial^2 u}{\partial y^2}\right)^2</math> || <math>0</math><br />
|-<br />
|<math>\epsilon_{wall}</math> || <math>0</math> || <math>0</math> || <math>\nu \, \left( \frac{\partial \sqrt{k}}{\partial y} \right)^2</math><br />
|-<br />
|<math>C_{\epsilon_1}</math> || <math>1.35</math> || <math>1.44</math> || <math>1.45</math><br />
|-<br />
|<math>C_{\epsilon_2}</math> || <math>1.8</math> || <math>1.92</math> || <math>1.9</math><br />
|-<br />
|<math>f_\mu</math> || <math>1-\exp{-0.0115 y^+}</math> || <math> \exp{\frac{-3.4}{\left( 1 + R_t/50 \right)^2}}</math> A || <math>\left(1-\exp{\frac{-y^+}{26}}\right)^2 \left(1+\frac{4.1}{Re_t^{3/4}}\right)</math><br />
|-<br />
|<math>f_1</math> || <math>1</math> || <math>1</math> || <math>1</math><br />
|-<br />
|<math>f_2</math> || <math>1-0.22 \exp{-\left(\frac{Re_t}{6}\right)^2}</math> || <math>1-0.3 \exp{-Re_t^2}</math> || <math>\left(1\!-\!0.3\exp{-\left(\frac{Re_t}{6.5}\right)^2}\right)\!\! \left(1\!-\!\exp{\frac{-y^+}{6}}\right)^2</math><br />
|}<br />
Where <math>Re_t \equiv \frac{k^2}{\nu \epsilon}</math>, <math>y^+ \equiv \frac{u^*y}{\nu}</math> and <math>k_{wall} = 0</math>.<br />
<br />
A According to P. Gardin, M.Brunet, J.F.Domgin and K. Pericleous, "An experimental and numerical CFD study of turbulence in a tundish container", 2nd International Conference on CFD, CSIRO, 1999. There are three options for <math>f_\mu</math><br />
<br />
<br />
D1<br />
<br />
<math> \min \left( 1.0 , \frac{R_t^{1/3}}{45} \right)</math><br />
<br />
<br />
D2<br />
<br />
<math> 1 - \exp{\frac{-R_t}{ 30.1862 }}</math><br />
<br />
<br />
D3<br />
<br />
<math> \exp{\frac{-3.4}{\left( 1 + R_t/50 \right)^2}}</math><br />
<br />
==Performance, applicability and limitations==<br />
<br />
''Not written yet''<br />
<br />
==Implementation issues==<br />
<br />
''Not written yet''<br />
<br />
==References==<br />
<br />
{{reference-paper|author=Chien, K.-Y.|year=1982|title=Predictions of Channel and Boundary-Layer Flows with a Low-Reynolds Number Turbulence Model|rest=AIAA Journal, Vol. 20, No. 1, pp. 33-38}}<br />
<br />
{{reference-paper|author=Nagano, Y. and Tagawa, M.|year=1990|title=An Improved k-epsilon Model for Boundary Layer Flows|rest=Journal of Fluids Engineering, Vol. 112, pp. 33-39}}<br />
<br />
{{reference-paper|author=Patel, V. C. and Rodi, W. and Scheuerer, G.|year=1985|title=Turbulence Models for Near-Wall and Low Reynolds Number Flows: A Review|rest=AIAA Journal, Vol. 23, No. 9, pp. 1308-1319}} <br />
<br />
{{reference-paper|author=Rodi, W. and Mansour, N. N.|year=1993|title=Low Reynolds Number k-epsilon Modeling with the Aid of Direct Simulation Data|rest=Journal of Fluid Mechanics, Vol. 250, pp. 509-529}}<br />
<br />
{{reference-paper|author=Launder, B. E. and Sharma, B. I.|year=1974|title=Application of the Energy-Dissipation Model of Turbulence to the Calculation of Flow Near a Spinning Disc|rest=Letters in Heat and Mass Transfer, Vol. 1, No. 2, pp. 131-138}}</div>Jasondhttp://www.cfd-online.com/Wiki/Talk:Fluent_FAQTalk:Fluent FAQ2007-08-18T15:11:42Z<p>Jasond: </p>
<hr />
<div>I'm not sure that the question about Forum posting is the most important FAQ, and I it think would be better placed as part of a Forum FAQ (which we don't currently have...). While I agree that text-message-style posts are not the greatest, we have little chance of changing the culture here. I have softened the wording accordingly (and made some other editorial changes). Personally, I will answer a post as long as I can understand it (SMS abbreviations or not). In my opinion, the wording on the ANSYS FAQ should also be changed. --[[User:Jasond|Jasond]] 09:11, 18 August 2007 (MDT)<br />
<br />
Please don't use this FAQ as a kind of discussion forum where you can just write your questions. The FAQ is the place where already answered questions from the forums should be written. --[[User:Jola|Jola]] 02:35, 22 March 2007 (MDT)<br />
<br />
In case you have missed it there is an old fluent FAQ available [[CFD-Wiki:Donated_texts| here]]. If you feel like helping out a bit please take some time to go through this FAQ and move the questions and answers that are still relevant and interesting into this CFD-Wiki Fluent FAQ. --[[User:Jola|Jola]] 13:18, 14 December 2005 (MST)<br />
<br />
I have added some of the questions/answers from the old FAQ, and I left them in the form of the old FAQ (with Q's and A's to distinguish them from the new content). Once I'm through adding, I'll either remove the Q's and A's or add them to the rest of the questions. --[[User:Jasond|Jasond]] 10:40, 22 July 2006 (MDT)</div>Jasondhttp://www.cfd-online.com/Wiki/Fluent_FAQFluent FAQ2007-08-18T15:09:56Z<p>Jasond: Added a couple of general questions, edited forum-related question (see talk page)</p>
<hr />
<div>This article contains questions and answers on the use of Fluent products (mainly Fluent and Gambit). Please feel free to add questions and answers here!<br />
<br />
== General Information ==<br />
<br />
=== What is Fluent? ===<br />
There are two answers to this question: Fluent (the company) is a CFD software company that is now part of ANSYS Inc. Fluent (the software package) is a popular commercial CFD package.<br />
<br />
=== What is Gambit? ===<br />
Gambit is a meshing software package that is typically purchased{{Fact}} with Fluent.<br />
<br />
=== How can I learn Fluent and Gambit? ===<br />
<br />
The documentation provided by Fluent is actually quite good, so it is a very good place to start. Fluent also provides tutorials and documentation<br />
on the [http://www.fluentusers.com fluentusers] site, which is open to everyone with a<br />
(full) license. Without a full commercial license, it is possible to use the tutorials given at [http://www.studentfluent.com/ studentfluent], or you may be able to register to use the user services center through other channels (e.g. through the university program). There are also some good tutorials available at [http://instruct1.cit.cornell.edu/courses/fluent/index.htm Cornell] and at various other places on the web (Google is a good place to start).<br />
<br />
=== Using CFD-Online's Fluent Forum ===<br />
<br />
==== How should I ask my question on the Fluent forum to get the most useful answer? ====<br />
<br />
It is important to understand that the quality of the answer to your question depends upon how well you ask your question. Many of the questions posted on the Fluent forum are so poorly posed that it is very difficult to understand what the poster is actually asking. Here are some suggestions to avoid this problem:<br />
<br />
# Make sure your question is as clear, concise, and as specific as possible. Other forum readers are unlikely to spend time trying to decipher a garbled question.<br />
# Give a clear general description of what class of problem and/or application you are working on before you start asking specific questions. This will aid other forum readers to better understand your specific questions.<br />
# Describe precisely what you have done yourself to try and solve your problem, giving examples.<br />
# Depending on your problem, you should try to include the following:<br />
#*If you are asking a mesh quality related question then include some sample images of your mesh, including the boundary layer.<br />
#*If you are asking a UDF question then include a copy of your existing code file as an attachment or in your post using <nowiki><pre></nowiki> tags to keep the code legible.<br />
<br />
==== How do I upload images? ==== <br />
* Create the image on your local machine e.g. skew_mesh.jpg<br />
* Upload the image to [http://www.imageshack.us Imageshack]<br />
* Copy the link "Thumbnail for websites"<br />
* Paste the link into your post e.g. <i><nowiki><a href="http://img91.imageshack.us/my.php?image=pipeym8.jpg" target="_blank"><img src="http://img91.imageshack.us/img91/5681/pipeym8.th.jpg" border="0" alt="Free Image Hosting at www.ImageShack.us" /></a></nowiki></i><br />
<br />
==== How do I share non-image files as attachments? ====<br />
* If you have more than one file, zip them into a single file.<br />
* Upload the file to [http://www.rapidshare.de Rapidshare] [http://www.gigasize.com/ Gigasize]<br />
* Scroll down to "I don't want a collector's account right now. Just give me the download-link." and click it.<br />
* Scroll down until you see the link e.g. <i><nowiki>http://rapidshare.de/files/33808646/audio.log.html</nowiki></i><br />
<br />
== FLUENT ==<br />
=== Solver Related ===<br />
==== What does "floating point error" mean? How can I avoid it? ====<br />
<br />
The floating point error has been reported many times and discussed a lot. Here are some of the answers found in the Fluent Forum:<br />
<br />
From numerical computation view point , the basic operations performed by computer are represented inside computer in what is called floating point numbers. The errors that are either because of invalid numeric computation initiated by user or limitation of machine that is used are floating point errors.<br />
<br />
1)Invalid Operations:- Simplest example is if one uses Newton Raphson root finding method to solve f(x)=0 and for some Nth iteration if we get x = x(N) such that derivative of function f(x), f'(x(N))=0 then formula for calculating next iterate x(N+1) = x(N) - f(x(N))/f'(x(N)) requires division by f'(x(N)) which is zero. Here you get divide by zero type of floating point error.<br />
<br />
2) Over or Underflow:- Another type is having data with either too large or too small magnitude called 'overflow' or 'underflow' respectively.Such data cannot be physically represented on computer for direct processing by arithmetic processing part of Processor. <br />
<br />
3) Rounding off errors :- While rounding off a decimal number , some significant digits are lost which cannot be recovered .<br />
e.g. if we round off 0.1 to integer (not greater than it called 'floor' of the given no.) then it is zero. If this value if further used for computation then it may lead to several errors.<br />
<br />
'''SOLVER AND ITERATION''' -----I think if you set shorter time step, it may be good. Or changing little Under-Relaxiation-Factors, it may be good. In my experience, I set 1/3 Under-Relaxiation-Factors as default.� -----�also lower the values of under relaxation factor and use the coupled implicit solver� -----�Try to change under-relaxation factors and if it is unsteady problem maybe time step is to large.� -----�you can improve the ratio in the solve--control--limits, maybe that can help.� -----�you will need to decrease the Courant number� -----�If you still get the error, initialize the domain with nothing to 'Compute from...' Then click 'init'. Again select the surface from which you want to compute the initial values & iterate. This should work.� -----�Another reason could be a to high courant number - that means, that the steps between two iterations are too large and the change in the results is too large as well (high residuals)�<br />
<br />
'''GRID PROBLEMS''' -----�this error comes when I start scaling grid. in gambit, all my dimension is in mm, when in fluent i convert it in meter using buttone SCALE. after it, when i iterate, about hundred iteration, this error appeared. but when i not scale my drawing to m...and let it be as in gambit..then the iteration is success. -----�hi I think you should check your mesh grid mesh is very high. your problem solve by selection a low mesh.� -----�Your mesh is so heavy that your computers resources are not enough. try to use coarser mesh.�<br />
<br />
'''BOUNDARY CONDITIONS''' -----�In my case I had set a wall boundary condition instead of an axis boundary condition and then FLuent refuses to calculate telling me 'floating point error'.� -----�Your Boudary Conditions do not represent real physis.� -----�wrong boundary condition definition might cause the floating point error. For example setting an internal boundary as interior� -----�Once I had the problem, simulating a 2D chamber with a symmetry BC. I set the symmetry somewhere as �axe symmetric� and the floating point error occur� -----�check the turbulence parameter you set. reduce the turbulence intensity to less that one for first, say 50 iterations.<br />
<br />
'''MULTI PROCESSOR ISSUES''' -----"I've had similar problems recently with floating point errors on a multi processor simulation. The solution for my problem seems to be to run on a single processor, where it runs fine....?�<br />
<br />
'''WRONG INITIATION''' ----- Initiating the case with wrong conditions may lead to floating point error when the iterations start.<br />
<br />
==== What is the difference between the coupled and the segregated solver? ====<br />
In the latest Fluent release,6.3.26 these are referred as density based and pressure based solvers.<br />
<br />
The coupled solver will solve all equations (conservation equations for mass, momentum and energy) simultaneously instead of sequentially (the equations are segregated from one another). You should use the coupled solver when the velocity and pressure are strongly coupled (high pressures and high velocities), but very long calculation times may be required when you use the coupled solver.<br />
<br />
In the coupled solvers, the Species Diffusion Term is always included in the energy equation.<br />
<br />
When you use the segregated solver, FLUENT allows you to specify anisotropic conductivity for solid materials<br />
<br />
From the [http://www.cfd-online.com/Forum/fluent_archive.cgi?read=40127 Fluent forum]:<br />
<br />
Choice of solvers depends heavily on the model being solved. The segregated solver solution is based on the pressure, while the coupled solver solution is based on density. This makes the segregated solver better at low speed flows and the coupled solver better at solving transonic / supersonic cases. I wouldn't recommend the coupled solver at any flows below Mach .4 (until the pressure based coupled solver comes out in the next release of Fluent). I've used the Segregated solver up to Mach 1.5 with great results, but the higher speed, the more mesh dependent you become (because the segregated solver tends to "smooth out" shocks), so you have to pay a lot of attention to your meshing.<br />
<br />
The coupled solver tends to be more stable with the defaults settings. The segregated solver tends to be very sensitive to the allowable limits. When trying to get a solution with the segregated solver, DO NOT increase the turbulent viscosity ratio limit (unless you have a great reason to based on past experience or the physics of your current model truly exceeding that limit, but I've never even heard of that being realistic). Instead limit the pressure and temperature limits to reasonable limits (i.e. Plimits = Pstatic +/- (2 * dynamic pressure), and calculate the appropriate temps). You need to give the solution "room to move" while it reaches a solution, but you don't want to give it enough room where it goes out to some totally impossible numbers, and the limits help prevent this.<br />
<br />
=== Model Related ===<br />
==== What is the turbulent viscosity ratio warning and how can I handle it? ====<br />
The problem can be caused by improper values for the boundary condition turbulence parameters. Check the fluent manual (which is kind of more like a textbook), about modeling turbulence.<br />
<br />
For the case of internal flow, you basically have to consider the physical state of the fluid upon entrance to your control volume. If the fluid is coming into your volume from a fully developed turbulent pipe flow, it will have more turbulent energy than from a stagnant fluid. Think of lots of little vortices, which mostly mix things up, and those all have kinetic energy associated). This energy can be expressed as a nondimensional Intensity (a percentage is used). In addition, a Length parameter is specified.<br />
<br />
==== How can I determine the inputs for a porous media or porous jump from flow versus pressure drop data? ====<br />
If you have pressure drop versus velocity data, you can fit the following equation through the data:<br />
<br />
<math>\Delta P = Av^2 + Bv</math><br />
<br />
where <math>\Delta P</math> is the pressure drop and <math>v</math> is the velocity. The coefficients <math>A</math> and <math>B</math> are related to the Fluent variables for the permeability <math>\alpha</math>, and the pressure coefficient <math>C_2</math> by<br />
<br />
<math>A = \frac{C_2 \rho \Delta n}{2}</math> and <math>B=\frac{\mu}{\alpha}\Delta n</math><br />
<br />
where <math>\Delta n</math> is the thicknes of the medium.<br />
<br />
==== How do I model heat conduction in a composite wall? ====<br />
<br />
==== What pressures should be specified at inlets and outlets for buoyancy flow problems? ====<br />
<br />
what pressures at inlet and outlet should specified in natural convection?<br />
<br />
==== Are there any general guidelines on selecting a turbulence model? ====<br />
<br />
==== How can both turbulent and laminar flow be included in one model? ====<br />
<br />
Depends. Fluent cannot presently compute boundary layer instability and subsequent transition to turbulence using a RANS approach (ke, SST, RSM etc). CFX has a new feature to do this, so perhaps it will be incorporated into Fluent soon as they are both owned by ANSYS.<br />
<br />
You therefore have two options : <br />
<br />
1. If you know the point of transition (like on an aircraft wing) from experimental data or DNS simulations, you can impose laminar flow in some regions by meshing a separate fluid region, and enabling "laminar zone" for this region in boundary settings. That is also useful in heat transfer cases, if for example you have turbulent flow one side of a thermal wall, and natural convection on the other side.<br />
<br />
2. A "near-wall" turbulence approach : Either k-omega, SST, or Low Reynolds k-E (which you have to select from the "Turbulence modelling/expert" menu), will damp turbulence near to the wall, either by empirical damping of turbulent "k" (Low Reynolds k-E) or by full solution of the omega equation on a fine enough mesh (k-omega/SST). If you have flows in small gaps in a larger, turbulent domain, in which large lengthscales of turbulence of course could not be supported, the flow will re-laminarise in a physically sensible (although perhaps not mathematically exact) manner. These models will also MAINTAIN laminar flow in external boundary layers, PROVIDED that you have a fine enough mesh (use the laminar mesh distribution guidelines in Fluent manual, too coarse a mesh will lead to non-physical turbulence generation in the BL). BUT they will maintain this laminar flow and evolution of the laminar profile (in the absence of significant disturbance by separation or impingement at the wall) forever, no spontaneous instability or transition to turbulence will occur. So check the length-based Reynolds numbers of walls where you think there will be undisturbed laminar boundaries, that there is not expected to be spontaneous transition of these BLs.<br />
<br />
==== How to start a 3D simulation with an compressible medium and temperature changes? What is important to consider ====<br />
<br />
<br />
I would do it that way:<br />
<br />
1. solve the flow for incompressible medium, without energy equation. Set the density close to the density, that you expect at the present pressure and temperature. The solution for the flow dosn't has to be completely convergent, but the residuals should be on the way down. <br />
<br />
2. Apply energy equation and compressibility of the gas and set the present pressure with operating condition option. You might do some iteration steps as well. Sometimes they are not necessary<br />
<br />
3. Apply the thermal BC<br />
<br />
=== Solution Methodology === <br />
==== How do I carry out rotating body analysis, eg a rotating sphere or cylinder''' in flo'''w? ====<br />
Rotating cylinder problem ( assume circular ), can be done easily by specifying angular velocity on the cylinder wall. As i observed no need of moving mesh for this case. you need to specify the rotation axis with respect to which your cylinder is rotating.<br />
<br />
==== How do I get better and faster convergence? ====<br />
==== What is the role of under-relaxation parameters? What should be the optimum choice of these parameters? ====<br />
They limit the influence of the previous iteration over the present one. If you choose small values it may prevent oscillations in residuum developing. At the same time the solution may need more time to converge. <br />
Keep the default values as they are given in FLUENT. You can decrease them gradually if necessary. Momentum 0.6, pressure 0.1, k 0.4, eps 0.4, mass source 1, viscosity 1.<br />
<br />
=== User-Defined Function (UDF) Related ===<br />
<br />
==== How do I learn UDF programming? ====<br />
There are not to many tutorials out there on this, probably due to the wide variety of things you can do with the UDF interface. The documentation the Fluent provides is pretty good once you know what you are trying to do (chapter 8 of the UDF manual has examples). UDF programming is easier if you have C programming experience, so it is advisable to learn a little C programming, then do some of the simple cases that Fluent provides, then tackle the problem you really want to solve. <br />
<br />
==== How do I create/build/load a UDF? ====<br />
The simplest way to add a UDF into Fluent is to write your UDF in the C programming language and then use Define -> User-Defined -> Functions to either interpret or compile your UDF. It can then be loaded. Fluent provides good documentation of the UDF interface with numerous examples, so read that before trying too much.<br />
<br />
==== Do I have to use C? ====<br />
Yes and no. To hook your UDF into Fluent, you'll probably have to use one of the DEFINE_* macros that Fluent provides, and this is most easily done using C. However, you can write routines that are used in the routines that are defined with the DEFINE_* macros in other languages and then link them together. This requires some knowledge of mixed language programming, Makefiles, the text user interface (TUI), and is not necessarily very portable. An example using Fortran is given in Section 5.4.1 of the Fluent UDF Manual (version 6.3).<br />
<br />
==== Which compilers work? ====<br />
On Unix-like machines, GCC is the compiler of choice. On Windows machines, Microsoft Visual C++ is the compiler of choice (GCC may also work on Windows- if anyone has firsthand knowledge of this, please share). The free Express Edition of the Microsoft compiler also works.<br />
<br />
==== My UDF won't interpret or compile - what is wrong? ====<br />
The answer depends upon what exactly has happened. <br />
<br />
*If Fluent complains about not being able to find a compiler, then check to make sure that the compiler is properly installed. On Windows machines, it is possible to install the Visual C++ compiler without fully setting up the command line compiler (which Fluent needs to be able to find). During the installation process, you need to select the "register environment variables" option. Failure to do so will likely lead to complaints about things being "not recognized as an internal or external command, operable program or batch file" or missing DLL's. It is theoretically possible to fix this issue by setting the appropriate environment variables, but keep in mind that even when nmake can be found there still may be DLL issues. The easy path is probably reinstallation of Visual Studio (taking special care to make sure that the command line interface is set up properly), but the reinstallation path is always perilous. If you have long-term experience using Windows you should probably know the risks, and if you don't you should consult an expert.<br />
<br />
*If you are interpreting, keep in mind that not everything that is supported for compiled UDF's is supported for interpreted UDF's. This is true both for the UDF interface and the C language. If you are doing something pretty involved and it fails inexplicably, try compiling to see if that makes a difference.<br />
<br />
*There is also the possibility of coding errors. Keep in mind that your source code gets run through the C preprocessor (to change the Fluent macros into C code), so unintended interactions are very possible.<br />
<br />
==== Why do I get the message "'nmake' is not recognized as an internal or external command, operable program or batch file"? ====<br />
This is a Windows/Visual Studio issue. In order to compile your UDF, Fluent needs to know where the nmake program is located, and it currently can't find it. If you open up a command window and enter "nmake", you should probably get the same message. See the previous question/answer.<br />
<br />
==== My UDF interprets/compiles but fails to execute - what is wrong? ====<br />
This commonly occurs due to a faulty operation of some kind. For example, user-defined memory (UDM) is not allocated until initialization, so attempting to access a UDM variable before initialization can lead to a segmentation fault. Try to isolate the cause, and then look for places where your expectation of what is available may not match reality. Finally, keep in mind that if you do something really bad, you may need to restart Fluent before even a fixed UDF will work.<br />
<br />
=== Journal File and Text User Interface (TUI) Related ===<br />
==== What is the Text User Interface? ====<br />
The Text User Interface (TUI) is a command-line-like interface to Fluent. The TUI is accessed through the main Fluent (hit enter while in the main Fluent window), with a menu system and the ability to execute Scheme programs. Fluent's documentation compares the menu system to the UNIX directory structure. Since it is text base, you can create and modify sequences of TUI commands using a simple text editor (see journal files below).<br />
<br />
When Fluent starts, you are in the "root" menu: press enter and you'll see something like this:<br />
<pre><br />
><br />
adapt/ file/ report/<br />
define/ grid/ solve/<br />
display/ parallel/ surface/<br />
exit plot/ view/<br />
</pre><br />
To access the plot menu, just type in "plot" and then press enter. To bring up the available commands, press enter again:<br />
<pre><br />
> plot<br />
<br />
/plot> <br />
change-fft-ref-pressure file-set/ residuals<br />
circum-avg-axial flamelet-curves residuals-set/<br />
circum-avg-radial histogram solution<br />
fft histogram-set/ solution-set/<br />
file plot<br />
file-list plot-direction<br />
</pre><br />
<br />
To exit a menu, simply type "q" and press enter (the rough equivalent of "cd .." in Unix). The TUI also understands command abreviations, so "pl/rs" is interpreted as "plot/residuals-set".<br />
<br />
==== What is a journal file? ====<br />
A journal file is a series of TUI commands stored in a text file. The file can be written in a text editor or generated by Fluent as a transcript of the commands given to Fluent during your session. A journal file generated by Fluent will include any GUI operations (in a TUI form, though). This is quite useful if you have a series of tasks that you need to execute, as it provides a shortcut. To record a journal file, start recording with File -> Write -> Start Journal..., perform whatever tasks you need, and then stop recording with File -> Write -> Stop Journal...<br />
<br />
==== How do I add a comment in a journal file? ====<br />
Any line beginning with a ''';''' (semicolon) is treated as a comment.<br />
<br />
==== How do I set boundary conditions? ====<br />
Suppose we have a boundary named "south" that we want to set as a wall. The command is<br />
<pre><br />
/define/boundary-conditions/zone-type south wall<br />
</pre><br />
which sets the zone "south" as a wall. The details (moving wall, etc.) can then be accessed be executing<br />
<pre><br />
/define/boundary-conditions/wall south<br />
</pre><br />
in the text user interface.<br />
<br />
==== How do I write a XY-plot? ====<br />
look at<br />
http://www.cfd-online.com/Forum/fluent_archive.cgi?read=40200<br />
<br />
==== How do I set material properties? ====<br />
look at http://www.cfd-online.com/Forum/fluent_archive.cgi?read=38768<br />
<br />
one example:<br />
<br />
<pre><br />
//define/materials/delete<br />
air_50c<br />
//define/materials/delete<br />
air_1bar<br />
//define/materials/change-create<br />
air<br />
air_1bar<br />
y<br />
incompressible-ideal-gas<br />
y<br />
piecewise-linear<br />
2<br />
298.15<br />
1007<br />
323.15<br />
1008<br />
y<br />
piecewise-linear<br />
2<br />
298.15<br />
0.02606<br />
323.15<br />
0.02788<br />
y<br />
piecewise-linear<br />
2<br />
273.15<br />
1.72E-05<br />
433.15<br />
2.45E-05<br />
n<br />
n<br />
n<br />
n<br />
n<br />
n<br />
y<br />
</pre><br />
<br />
==== How do I generate a hardcopy of a window? ====<br />
<br />
<pre><br />
display set-window 1 ; if window nr. 1 is the window you want to be hardcopied<br />
//display/set/windows/scale/form ; setting the options for the graph (colourmap)<br />
"%0.2f"<br />
//display/set/color-ramp<br />
bgr<br />
//display/set/hardcopy/color ; setting the options for the window<<br />
color<br />
//display/set/hardcopy/driver<br />
tiff<br />
//display/set/hardcopy/y-res<br />
2400<br />
//display/set/hardcopy/x-res<br />
3106<br />
//display/set/hardcopy/inv<br />
no<br />
//display/hard<br />
filename.tiff<br />
//display/set/hardcopy/inv<br />
yes<br />
//display/hard<br />
filename_inv.tiff<br />
</pre><br />
<br />
==== How do I run multiple cases in batch mode? ====<br />
This could be achieved by running it from journal file. The example journal file that runs two cases is given as:<br />
<pre><br />
file read-case-data xxx1.cas<br />
solve dual-time-iterate yyy1<br />
file write-case-data zzz1.cas<br />
file read-case-data xxx2.cas<br />
yes ; for discard cas dialog<br />
solve dual-time-iterate yyy2<br />
file write-case-data zzz2.cas<br />
</pre><br />
<br />
<br />
Another example:<br />
<pre><br />
rcd filemname.cas<br />
yes<br />
it 10000 <br />
wcd filemname.cas <br />
yes<br />
</pre><br />
<br />
<br />
Have a look at this discussion: [http://www.cfd-online.com/Forum/fluent_archive_2005.cgi/read/32615 http://www.cfd-online.com/Forum/fluent_archive_2005.cgi/read/32615]<br />
<br />
==== How do I loop in a journal file? ====<br />
The best way to loop in a journal file (or the text user interface) is to use one of the Scheme programming language's looping constructs.<br />
<br />
=== Tips === <br />
==== How do I merge two mesh files into one mesh file? ====<br />
To merge two mesh files the suggested utility is tmerge. The syntax of tmerge is simple.<br><br />
<i>utility tmerge -3d file1 file2 finalfile </i> <br><br />
To join the two interior faces use: <br><br />
<i>Grid->Fuse</i> <br><br />
from the menu with Fluent.<br />
<br />
==== How do I export Fieldview data for postprocessing during iterations? ====<br />
<br />
This could be done with the help of menu <b>solve->Execute Commands </b>. <br />
Here are two examples:<br />
<br />
'''Steady Case'''<br />
<br />
<pre><br />
file/export/fug/File_grid-%n<br />
file/export/fud/File_data-%n pressure velocity-magnitude x-velocity y-velocity z-velocity () </pre><br />
<br />
'''Unsteady Case'''<br />
<br />
<pre><br />
file/export/fug/File_grid-%t<br />
file/export/fud/File_data-%t pressure velocity-magnitude x-velocity y-velocity z-velocity () </pre><br />
<br />
You can chose the frequency of export from the <b>Execute Command</b> panel.<br />
<br />
==== What does abbreviation X mean?====<br />
<br />
{| border="1"<br />
|- <br />
| APG || adverse pressure gradient<br />
|- <br />
| BC || Boundary Conditions<br />
|- <br />
| B-L || Boundary Layer<br />
|-<br />
| CFD || Computational Fluid Dynamics<br />
|-<br />
| DES || Detached Eddy Simulation<br />
|-<br />
| DPM || Discrete Phase Model<br />
|-<br />
| FDM || Finite Difference Method<br />
|-<br />
| FEM || Finite Element Method<br />
|-<br />
| FVM || Finite Volume Method<br />
|-<br />
| GUI || Graphical User Interface<br />
|-<br />
| LES || Large Eddy Simulation<br />
|-<br />
| MUSCL || Monotone Upstream-centered Scheme for Conservation Laws<br />
|-<br />
| MDM || Moving and Deforming Mesh<br />
|-<br />
| PDF || Probability Density Function<br />
|-<br />
| QUICK || Quadratic Upstream Interpolation for Convective Kinematics<br />
|-<br />
| RANS || Reynolds Averaged Navier-Stokes<br />
|-<br />
| RSM || Reynolds Stress Model<br />
|-<br />
| SIMPLE || Semi-Implicit Method for the Pressure-Linked Equation<br />
|-<br />
| SST || Shear Stress Transport<br />
|-<br />
| TUI || Text User Interface<br />
|-<br />
| UDF || User defined function<br />
|-<br />
| URF || Under Relaxation Factor<br />
|-<br />
| VOF || Volume Of Fluid<br />
|}<br />
<br />
==== What is the difference between FE and FV?====<br />
<br />
See the answer in the [[General CFD FAQ#What is the difference between FEM, FVM and FDM?|General CFD FAQ]].<br />
<br />
== FloWizard==<br />
<br />
== FIDAP==<br />
<br />
== POLYFLOW ==<br />
<br />
== Gambit ==<br />
===Why does Gambit refuse to open my .dbs file and say that my file is already open? I get an error message - ERROR: IDENTIFIER "X" CURRENTLY OPEN.===<br />
Before opening your file "X.dbs", Gambit looks for a file named "X.lok" to determine the status of your file. If it finds the .lok file, you'll get the above error message (or something like it). If you are in a multi-user environment, you should check that it is not actually already open elsewhere, but in other situations the most likely reason that there is still a X.lok file is that Gambit encountered a problem the last time X.dbs was open. Deleting the .lok file should solve your problem.<br />
<br />
===Q: Why does Gambit complain about the number of nodes on edges being odd and then refuse to mesh a face?===<br />
<br />
A: It is mathematically impossible to create an all-quad mesh with an odd number of intervals on the outer edge loop. If this is inconvenient for you, you may consider a quad-dominant mesh (mostly quads, with a few triangles), or even an all-triangle mesh. Many users achieved good solutions with triangle surface meshes and prism (wedge) boundary layers.<br />
<br />
===Q: What are these boundary layers things defined in Gambit? Do they represent the real situation?===<br />
<br />
A: Gambit's boundary layers allow you to generate specific semi-structured grids topologies on faces that grow out from an edge or edges. You can specify the initial cell height, the growth rate, and a transition pattern that changes the edge-parallel interval count. There are several default settings, which can affect the quality of boundary layers. For cases with sharp corners, normal and offset smoothing can greatly improve quality. Such smoothing is off by default because it requires significantly more computation time.<br />
<br />
===Q: If my quad face mesh has cells with high skewness or large aspect ratios, the pyramiding procedure used by the tet mesher will frequently lead to failure, why? ===<br />
<br />
A: This is because the triangles on the tops of the pyramids have very high skewnesses which can prevent tet meshing. Consider a quad face with a 10-to-1 aspect ratio. Connect opposite corners to create diagonals. This is the "top view" of the pyramid that would be created on this face. The triangles are very highly skewed. It is recommended that your quad faces bounding a region to be tet-meshed have aspect ratios of 5-to-1 or lower.<br />
<br />
===Q: I'm trying to mesh a geometry but I'm getting this message: “check the skewnesses of you face meshes and make sure the face mesh sizes are not too large in areas of small gaps.” I checked the skewness and it's low enough. ===<br />
<br />
A: Your problem is most likely that you have small gaps where the local surface mesh sizes are much larger than the gap sizes. Refining the surface meshes in those areas is likely to solve the problem.<br />
<br />
===Q: I would like to generate grids for different zones using Gambit. How do I merge them together using Gambit or Tgrid later?===<br />
<br />
A: For a valid conformal mesh, mesh nodes on the faces at the interface of the two parts have to be matching within a tolerance. Then, you can either merge the nodes (using Tgrid) or fuse the zones (using Fluent). If you use Tgrid to merge the duplicate nodes, the resulting surface at the interface will have the boundary type as "wall" which should be changed to "interior" if both sides of the interface have same cell (fluid) zone. Fluent automatically converts the resulting surface after fuse to be of "interior" type if both sides of it has the same cell (fluid) zone. <br />
<br />
Also, if you are not using Tgrid, you need to use tfilter tmerge3d to merge the meshes together before reading them into Fluent. Tgrid does the same when you load multiple mesh files at a time. <br />
<br />
===Q: How do I determine what kind of grid to generate? (I would like to known selection criteria between structured and unstructured mesh.)===<br />
<br />
A: Try this approach - consider the meshing options in this order: Single-Block Structured, Multi-Block Structured, Multi-Block Hybrid/Mixed, Fully Unstructured. Gambit can generate most of the cells types and topologies that Fluent can use (with the notable exception of nonconformal meshes). Here are some guidelines/suggestions:<br />
* If you can generate a single-block structured mesh for your problem, then stop there. There is no need to go further. <br />
* If your solution is having problem around a corner (or the like), try multi-block structured mesh. If you are getting improved solution, then stop there. <br />
* If you still have problems around different part of the corner, try the unstructured mesh, with high density mesh around the corner. Before going to a fully unstructured mesh, try making only the problem region unstructured. If the solution is good, then stop there. <br />
* If one part of the mesh still requires special attention, then you can use Fluent's adaptive unstructured facility to refine the mesh until the solution is acceptable. Ideally, you should still get a mesh independent solution. <br />
* It is very important to be able to control every part of your mesh so that you can get good solution everywhere. This is more difficult with unstructured meshes. <br />
* For many geometries, if you can use a structured mesh you will end up with fewer cells (this is particularly true in three dimensions). It is a good idea to use structured-type meshes in regions that will allow it, and use unstructured meshes everywhere else.<br />
* Don't forget that Fluent can handle prismatic cells. If you have an unstructured surface mesh, Gambit can generate a layer of prismatic cells that will resolve boundary layers without requiring a (fully) structured mesh.<br />
<br />
===Q: How do I run GAMBIT as a batch process?=== <br />
<br />
A: To run Gambit in "batch" mode, prepare a journal file (e.g., "test.jou"), then use the command : gambit test -in test.jou <br />
<br />
=== Q: I am having trouble uniting two volumes, what should I do? ===<br />
<br />
"misclassified graph coedge - probably geometrical problem" <br><br />
-> you can try healing the volumes<br><br />
-> deleting the volume (without lower geometry), healing and uniting the faces, then build the volume again<br />
<br />
===Q: I am trying to move a node to modify the mesh on a face with mouse. Why in y direction I can only move the node discretely by 0.5 or multiples of 0.5? I can move it continuously in x direction and I would like to do so in y as well. Is there some default value to change? ===<br />
<br />
== Other Preprocessing Codes==<br />
=== Gambit Turbo ===<br />
<br />
=== TGrid ===<br />
<br />
== Application specific codes ==<br />
<br />
=== Icepak ===<br />
<br />
=== Airpak ===<br />
<br />
=== MixSim ===<br />
<br />
== Educational codes ==<br />
<br />
=== FlowLab ===<br />
[http://flowlab.fluent.com]<br />
<br />
[[Category: FAQ's]]<br />
<br />
{{stub}}</div>Jasondhttp://www.cfd-online.com/Wiki/Ratio_of_specific_heatsRatio of specific heats2007-08-15T20:03:02Z<p>Jasond: </p>
<hr />
<div>The ratio of [[specific heats]] (also known as ''adiabatic index''), usually denoted by <math>\gamma</math>, is the ratio of [[specific heat]] at constant [[pressure]] to the [[specific heat]] at constant [[volume]]. {{Fact}}<br />
<br />
:<math><br />
\gamma \equiv \frac{C_p}{C_v}<br />
</math><br />
<br />
The adiabatic index always exceeds unity; for a [[polytropic gas]] it is constant.{{fact}} For [[monatomic gas]] <math>\gamma=5/3</math>, and for [[diatomic gases]] <math>\gamma=7/5</math>, at ordinary [[temperatures]].{{fact}} For air its value is close to that of a diatomic gas, 7/5 = 1.4.{{fact}}<br />
<br />
Sometimes <math>k</math> or <math>\kappa</math> is used instead of <math>\gamma</math> to denote the specific heat ratio.<br />
<br />
{{Stub}}</div>Jasondhttp://www.cfd-online.com/Wiki/Jacobi_methodJacobi method2007-08-13T19:46:59Z<p>Jasond: Improved questionable wording</p>
<hr />
<div>The Jacobi method is an algorithm in linear algebra for determining the solutions of a system of linear equations with largest absolute values in each row and column dominated by the diagonal element. Each diagonal element is solved for, and an approximate value plugged in. The process is then iterated until it converges. This algorithm is a stripped-down version of the Jacobi transformation method of matrix diagonalization. The method is named after German mathematician [http://en.wikipedia.org/wiki/Carl_Gustav_Jakob_Jacobi Carl Gustav Jakob Jacobi].<br />
<br />
We seek the solution to set of linear equations: <br><br />
<br />
:<math> A \phi = b </math> <br><br />
<br />
In matrix terms, the definition of the Jacobi method can be expressed as : <br><br />
:<math> <br />
\phi^{(k+1)} = D^{ - 1} \left[\left( {L + U} \right)\phi^{(k)} + b\right]<br />
</math><br><br />
<br />
where <math>D</math>, <math>L</math>, and <math>U</math> represent the diagonal, lower triangular, and upper triangular parts of the coefficient matrix <math>A</math> and <math>k</math> is the iteration count. This matrix expression is mainly of academic interest, and is not used to program the method. Rather, an element-based approach is used:<br />
<br />
:<math> <br />
\phi^{(k+1)}_i = \frac{1}{a_{ii}} \left(b_i -\sum_{j\ne i}a_{ij}\phi^{(k)}_j\right),\, i=1,2,\ldots,n.<br />
</math><br />
<br />
Note that the computation of <math>\phi^{(k+1)}_i</math> requires each element in <math>\phi^{(k)}</math> except itself. Then, unlike in the [[Gauss-Seidel method]], we can't overwrite <math>\phi^{(k)}_i</math> with <math>\phi^{(k+1)}_i</math>, as that value will be needed by the rest of the computation. This difference between the Jacobi and Gauss-Seidel methods complicates matters somewhat. Generally, two vectors of size <math>n</math> will be needed, and a vector-to-vector copy will be required. If the form of <math>A</math> is known (e.g. tridiagonal), then the additional storage should be avoidable with careful coding.<br />
<br />
== Algorithm ==<br />
Choose an initial guess <math>\phi^{0}</math> to the solution <br><br />
: for k := 1 step 1 until convergence do <br><br />
:: for i := 1 step until n do <br><br />
::: <math> \sigma = 0 </math> <br><br />
::: for j := 1 step until n do <br><br />
:::: if j != i then<br />
::::: <math> \sigma = \sigma + a_{ij} \phi_j^{(k-1)} </math><br />
:::: end if<br />
::: end (j-loop) <br><br />
::: <math> \phi_i^{(k)} = {{\left( {b_i - \sigma } \right)} \over {a_{ii} }} </math><br />
:: end (i-loop)<br />
:: check if convergence is reached<br />
: end (k-loop)<br />
<br />
==Convergence==<br />
The method will always converge if the matrix A is strictly or irreducibly diagonally dominant. Strict row diagonal dominance means that for each row, the absolute value of the diagonal term is greater than the sum of absolute values of other terms:<br />
<br />
:<math>\left | a_{ii} \right | > \sum_{i \ne j} {\left | a_{ij} \right |} </math><br />
<br />
The Jacobi method sometimes converges even if this condition is not satisfied. It is necessary, however, that the diagonal terms in the matrix are greater (in magnitude) than the other terms.<br />
<br />
== Example Calculation ==<br />
As with [[Gauss-Seidel method|Gauss-Seidel]], Jacobi iteration lends itself to situations in which we need not explicitly represent the matrix. Consider the simple heat equation problem <br />
<br />
:<math>\nabla^2 T(x) = 0,\ x\in [0,1]</math><br />
<br />
subject to the boundary conditions <math>T(0)=0</math> and <math>T(1)=1</math>. The exact solution to this problem is <math>T(x)=x</math>. The standard second-order finite difference discretization is<br />
<br />
:<math> T_{i-1}-2T_i+T_{i+1} = 0,</math><br />
<br />
where <math>T_i</math> is the (discrete) solution available at uniformly spaced nodes (see [[Gauss-Seidel method#Example Calculation|the Gauss-Seidel example]] for the matrix form). For any given <math>T_i</math> for <math>1 < i < n</math>, we can write <br />
<br />
:<math> T_i = \frac{1}{2}(T_{i-1}+T_{i+1}).</math><br />
<br />
Then, stepping through the solution vector from <math>i=2</math> to <math>i=n-1</math>, we can compute the next iterate from the two surrounding values. For a proper Jacobi iteration, we'll need to use values from the previous iteration on the right-hand side:<br />
<br />
:<math> T_i^{k+1} = \frac{1}{2}(T_{i-1}^{k}+T_{i+1}^k).</math><br />
<br />
The following table gives the results of 10 iterations with 5 nodes (3 interior and 2 boundary) as well as <math>L_2</math> norm error.<br />
{| align=center border=1<br />
|+ Jacobi Solution<br />
! Iteration !! <math>T_1</math> !! <math>T_2</math> !! <math>T_3</math> !! <math>T_4</math> !! <math>T_5</math> !! <math>L_2</math> error <br />
|-<br />
| 0<br />
| 0.0000E+00<br />
| 0.0000E+00<br />
| 0.0000E+00<br />
| 0.0000E+00<br />
| 1.0000E+00<br />
| 1.0000E+00<br />
|-<br />
| 1<br />
| 0.0000E+00<br />
| 0.0000E+00<br />
| 0.0000E+00<br />
| 5.0000E-01<br />
| 1.0000E+00<br />
| 6.1237E-01<br />
|-<br />
| 2<br />
| 0.0000E+00<br />
| 0.0000E+00<br />
| 2.5000E-01<br />
| 5.0000E-01<br />
| 1.0000E+00<br />
| 4.3301E-01<br />
|-<br />
| 3<br />
| 0.0000E+00<br />
| 1.2500E-01<br />
| 2.5000E-01<br />
| 6.2500E-01<br />
| 1.0000E+00<br />
| 3.0619E-01<br />
|-<br />
| 4<br />
| 0.0000E+00<br />
| 1.2500E-01<br />
| 3.7500E-01<br />
| 6.2500E-01<br />
| 1.0000E+00<br />
| 2.1651E-01<br />
|-<br />
| 5<br />
| 0.0000E+00<br />
| 1.8750E-01<br />
| 3.7500E-01<br />
| 6.8750E-01<br />
| 1.0000E+00<br />
| 1.5309E-01<br />
|-<br />
| 6<br />
| 0.0000E+00<br />
| 1.8750E-01<br />
| 4.3750E-01<br />
| 6.8750E-01<br />
| 1.0000E+00<br />
| 1.0825E-01<br />
|-<br />
| 7<br />
| 0.0000E+00<br />
| 2.1875E-01<br />
| 4.3750E-01<br />
| 7.1875E-01<br />
| 1.0000E+00<br />
| 7.6547E-02<br />
|-<br />
| 8<br />
| 0.0000E+00<br />
| 2.1875E-01<br />
| 4.6875E-01<br />
| 7.1875E-01<br />
| 1.0000E+00<br />
| 5.4127E-02<br />
|-<br />
| 9<br />
| 0.0000E+00<br />
| 2.3438E-01<br />
| 4.6875E-01<br />
| 7.3438E-01<br />
| 1.0000E+00<br />
| 3.8273E-02<br />
|-<br />
| 10<br />
| 0.0000E+00<br />
| 2.3438E-01<br />
| 4.8438E-01<br />
| 7.3438E-01<br />
| 1.0000E+00<br />
| 2.7063E-02<br />
|}<br />
<br />
<br />
==External links==<br />
*[http://www.math-linux.com/spip.php?article49 Jacobi method from www.math-linux.com]<br />
*[http://mathworld.wolfram.com/JacobiMethod.html Jacobi Method at Math World]<br />
*[http://en.wikipedia.org/wiki/Jacobi_method Jacobi method at Wikipedia]</div>Jasondhttp://www.cfd-online.com/Wiki/Talk:Tridiagonal_matrix_algorithm_-_TDMA_(Thomas_algorithm)Talk:Tridiagonal matrix algorithm - TDMA (Thomas algorithm)2007-07-27T15:26:59Z<p>Jasond: </p>
<hr />
<div>There is a mistake here. TDMA algoritms solves any kind of tridiagonal matrices. See Numerical Heat Transfer and Fluid Flow (ISBN 0-89116-522-3).<br />
:Well, I have not taken the time to verify you are correct (and I lack the time to), but you should probably just go ahead and edit it - the Wiki is a collaboration after all - and give a more specific reference (i.e. page number of the book you mention).--[[User:Jasond|Jasond]] 09:26, 27 July 2007 (MDT)</div>Jasondhttp://www.cfd-online.com/Wiki/Main_PageMain Page2007-07-27T15:23:14Z<p>Jasond: reverted vandalism</p>
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''"I consider it the obligation of scientists and intellectuals to ensure that their ideas are made accessible and thus useful to society instead of being mere playthings for specialists." '' --Bjarne Stroustrup, from "Design and Evolution of C++"</div>Jasondhttp://www.cfd-online.com/Wiki/Fluent_FAQFluent FAQ2007-06-29T20:24:04Z<p>Jasond: /* Do I have to use C? */</p>
<hr />
<div>This section is empty. This is just a suggestion on how to structure it. Please feel free to add questions and answers here!<br />
<br />
== Information ==<br />
<br />
=== Learning Material ===<br />
<br />
====How can I learn Fluent and Gambit?====<br />
<br />
The documentation provided by Fluent is actually quite good, so it is a very good place to start. Fluent also provides tutorials and documentation<br />
on the [http://www.fluentusers.com fluentusers] site, which is open to everyone with a<br />
(full) license. Without a full commercial license, it is possible to use the tutorials given at [http://www.studentfluent.com/ studentfluent], or you may be able to register to use the user services center through other channels (e.g. through the university program). There are also some good tutorials available at [http://instruct1.cit.cornell.edu/courses/fluent/index.htm Cornell].<br />
<br />
== FLUENT ==<br />
=== Solver Related ===<br />
==== What does "floating point error" mean? How can I avoid it? ====<br />
<br />
The floating point error has been reported many times and discussed a lot. Here are some of the answers found in the Fluent Forum:<br />
<br />
From numerical computation view point , the basic operations performed by computer are represented inside computer in what is called floating point numbers. The errors that are either because of invalid numeric computation initiated by user or limitation of machine that is used are floating point errors.<br />
<br />
1)Invalid Operations:- Simplest example is if one uses Newton Raphson root finding method to solve f(x)=0 and for some Nth iteration if we get x = x(N) such that derivative of function f(x), f'(x(N))=0 then formula for calculating next iterate x(N+1) = x(N) - f(x(N))/f'(x(N)) requires division by f'(x(N)) which is zero. Here you get divide by zero type of floating point error.<br />
<br />
2) Over or Underflow:- Another type is having data with either too large or too small magnitude called 'overflow' or 'underflow' respectively.Such data cannot be physically represented on computer for direct processing by arithmetic processing part of Processor. <br />
<br />
3) Rounding off errors :- While rounding off a decimal number , some significant digits are lost which cannot be recovered .<br />
e.g. if we round off 0.1 to integer (not greater than it called 'floor' of the given no.) then it is zero. If this value if further used for computation then it may lead to several errors.<br />
<br />
'''SOLVER AND ITERATION''' -----I think if you set shorter time step, it may be good. Or changing little Under-Relaxiation-Factors, it may be good. In my experience, I set 1/3 Under-Relaxiation-Factors as default.� -----�also lower the values of under relaxation factor and use the coupled implicit solver� -----�Try to change under-relaxation factors and if it is unsteady problem maybe time step is to large.� -----�you can improve the ratio in the solve--control--limits, maybe that can help.� -----�you will need to decrease the Courant number� -----�If you still get the error, initialize the domain with nothing to 'Compute from...' Then click 'init'. Again select the surface from which you want to compute the initial values & iterate. This should work.� -----�Another reason could be a to high courant number - that means, that the steps between two iterations are too large and the change in the results is too large as well (high residuals)�<br />
<br />
'''GRID PROBLEMS''' -----�this error comes when I start scaling grid. in gambit, all my dimension is in mm, when in fluent i convert it in meter using buttone SCALE. after it, when i iterate, about hundred iteration, this error appeared. but when i not scale my drawing to m...and let it be as in gambit..then the iteration is success. -----�hi I think you should check your mesh grid mesh is very high. your problem solve by selection a low mesh.� -----�Your mesh is so heavy that your computers resources are not enough. try to use coarser mesh.�<br />
<br />
'''BOUNDARY CONDITIONS''' -----�In my case I had set a wall boundary condition instead of an axis boundary condition and then FLuent refuses to calculate telling me 'floating point error'.� -----�Your Boudary Conditions do not represent real physis.� -----�wrong boundary condition definition might cause the floating point error. For example setting an internal boundary as interior� -----�Once I had the problem, simulating a 2D chamber with a symmetry BC. I set the symmetry somewhere as �axe symmetric� and the floating point error occur� -----�check the turbulence parameter you set. reduce the turbulence intensity to less that one for first, say 50 iterations.<br />
<br />
'''MULTI PROCESSOR ISSUES''' -----"I've had similar problems recently with floating point errors on a multi processor simulation. The solution for my problem seems to be to run on a single processor, where it runs fine....?�<br />
<br />
'''WRONG INITIATION''' ----- Initiating the case with wrong conditions may lead to floating point error when the iterations start.<br />
<br />
==== What is the difference between the coupled and the segregated solver? ====<br />
In the latest Fluent release,6.3.26 these are referred as density based and pressure based solvers.<br />
<br />
The coupled solver will solve all equations (conservation equations for mass, momentum and energy) simultaneously instead of sequentially (the equations are segregated from one another). You should use the coupled solver when the velocity and pressure are strongly coupled (high pressures and high velocities), but very long calculation times may be required when you use the coupled solver.<br />
<br />
In the coupled solvers, the Species Diffusion Term is always included in the energy equation.<br />
<br />
When you use the segregated solver, FLUENT allows you to specify anisotropic conductivity for solid materials<br />
<br />
From the [http://www.cfd-online.com/Forum/fluent_archive.cgi?read=40127 Fluent forum]:<br />
<br />
Choice of solvers depends heavily on the model being solved. The segregated solver solution is based on the pressure, while the coupled solver solution is based on density. This makes the segregated solver better at low speed flows and the coupled solver better at solving transonic / supersonic cases. I wouldn't recommend the coupled solver at any flows below Mach .4 (until the pressure based coupled solver comes out in the next release of Fluent). I've used the Segregated solver up to Mach 1.5 with great results, but the higher speed, the more mesh dependent you become (because the segregated solver tends to "smooth out" shocks), so you have to pay a lot of attention to your meshing.<br />
<br />
The coupled solver tends to be more stable with the defaults settings. The segregated solver tends to be very sensitive to the allowable limits. When trying to get a solution with the segregated solver, DO NOT increase the turbulent viscosity ratio limit (unless you have a great reason to based on past experience or the physics of your current model truly exceeding that limit, but I've never even heard of that being realistic). Instead limit the pressure and temperature limits to reasonable limits (i.e. Plimits = Pstatic +/- (2 * dynamic pressure), and calculate the appropriate temps). You need to give the solution "room to move" while it reaches a solution, but you don't want to give it enough room where it goes out to some totally impossible numbers, and the limits help prevent this.<br />
<br />
=== Model Related ===<br />
==== What is the turbulent viscosity ratio warning and how can I handle it? ====<br />
The problem can be caused by improper values for the boundary condition turbulence parameters. Check the fluent manual (which is kind of more like a textbook), about modeling turbulence.<br />
<br />
For the case of internal flow, you basically have to consider the physical state of the fluid upon entrance to your control volume. If the fluid is coming into your volume from a fully developed turbulent pipe flow, it will have more turbulent energy than from a stagnant fluid. Think of lots of little vortices, which mostly mix things up, and those all have kinetic energy associated). This energy can be expressed as a nondimensional Intensity (a percentage is used). In addition, a Length parameter is specified.<br />
<br />
==== How can I determine the inputs for a porous media or porous jump from flow versus pressure drop data? ====<br />
If you have pressure drop versus velocity data, you can fit the following equation through the data:<br />
<br />
<math>\Delta P = Av^2 + Bv</math><br />
<br />
where <math>\Delta P</math> is the pressure drop and <math>v</math> is the velocity. The coefficients <math>A</math> and <math>B</math> are related to the Fluent variables for the permeability <math>\alpha</math>, and the pressure coefficient <math>C_2</math> by<br />
<br />
<math>A = \frac{C_2 \rho \Delta n}{2}</math> and <math>B=\frac{\mu}{\alpha}\Delta n</math><br />
<br />
where <math>\Delta n</math> is the thicknes of the medium.<br />
<br />
==== How do I model heat conduction in a composite wall? ====<br />
<br />
==== What pressures should be specified at inlets and outlets for buoyancy flow problems? ====<br />
<br />
what pressures at inlet and outlet should specified in natural convection?<br />
<br />
==== Are there any general guidelines on selecting a turbulence model? ====<br />
<br />
==== How can both turbulent and laminar flow be included in one model? ====<br />
<br />
Depends. Fluent cannot presently compute boundary layer instability and subsequent transition to turbulence using a RANS approach (ke, SST, RSM etc). CFX has a new feature to do this, so perhaps it will be incorporated into Fluent soon as they are both owned by ANSYS.<br />
<br />
You therefore have two options : <br />
<br />
1. If you know the point of transition (like on an aircraft wing) from experimental data or DNS simulations, you can impose laminar flow in some regions by meshing a separate fluid region, and enabling "laminar zone" for this region in boundary settings. That is also useful in heat transfer cases, if for example you have turbulent flow one side of a thermal wall, and natural convection on the other side.<br />
<br />
2. A "near-wall" turbulence approach : Either k-omega, SST, or Low Reynolds k-E (which you have to select from the "Turbulence modelling/expert" menu), will damp turbulence near to the wall, either by empirical damping of turbulent "k" (Low Reynolds k-E) or by full solution of the omega equation on a fine enough mesh (k-omega/SST). If you have flows in small gaps in a larger, turbulent domain, in which large lengthscales of turbulence of course could not be supported, the flow will re-laminarise in a physically sensible (although perhaps not mathematically exact) manner. These models will also MAINTAIN laminar flow in external boundary layers, PROVIDED that you have a fine enough mesh (use the laminar mesh distribution guidelines in Fluent manual, too coarse a mesh will lead to non-physical turbulence generation in the BL). BUT they will maintain this laminar flow and evolution of the laminar profile (in the absence of significant disturbance by separation or impingement at the wall) forever, no spontaneous instability or transition to turbulence will occur. So check the length-based Reynolds numbers of walls where you think there will be undisturbed laminar boundaries, that there is not expected to be spontaneous transition of these BLs.<br />
<br />
==== How to start a 3D simulation with an compressible medium and temperature changes? What is important to consider ====<br />
<br />
<br />
I would do it that way:<br />
<br />
1. solve the flow for incompressible medium, without energy equation. Set the density close to the density, that you expect at the present pressure and temperature. The solution for the flow dosn't has to be completely convergent, but the residuals should be on the way down. <br />
<br />
2. Apply energy equation and compressibility of the gas and set the present pressure with operating condition option. You might do some iteration steps as well. Sometimes they are not necessary<br />
<br />
3. Apply the thermal BC<br />
<br />
=== Solution Methodology === <br />
==== How do I carry out rotating body analysis, eg a rotating sphere or cylinder''' in flo'''w? ====<br />
Rotating cylinder problem ( assume circular ), can be done easily by specifying angular velocity on the cylinder wall. As i observed no need of moving mesh for this case. you need to specify the rotation axis with respect to which your cylinder is rotating.<br />
<br />
==== How do I get better and faster convergence? ====<br />
==== What is the role of under-relaxation parameters? What should be the optimum choice of these parameters? ====<br />
They limit the influence of the previous iteration over the present one. If you choose small values it may prevent oscillations in residuum developing. At the same time the solution may need more time to converge. <br />
Keep the default values as they are given in FLUENT. You can decrease them gradually if necessary. Momentum 0.6, pressure 0.1, k 0.4, eps 0.4, mass source 1, viscosity 1.<br />
<br />
=== User-Defined Function (UDF) Related ===<br />
<br />
==== How do I learn UDF programming? ====<br />
There are not to many tutorials out there on this, probably due to the wide variety of things you can do with the UDF interface. The documentation the Fluent provides is pretty good once you know what you are trying to do (chapter 8 of the UDF manual has examples). UDF programming is easier if you have C programming experience, so it is advisable to learn a little C programming, then do some of the simple cases that Fluent provides, then tackle the problem you really want to solve. <br />
<br />
==== How do I create/build/load a UDF? ====<br />
The simplest way to add a UDF into Fluent is to write your UDF in the C programming language and then use Define -> User-Defined -> Functions to either interpret or compile your UDF. It can then be loaded. Fluent provides good documentation of the UDF interface with numerous examples, so read that before trying too much.<br />
<br />
==== Do I have to use C? ====<br />
Yes and no. To hook your UDF into Fluent, you'll probably have to use one of the DEFINE_* macros that Fluent provides, and this is most easily done using C. However, you can write routines that are used in the routines that are defined with the DEFINE_* macros in other languages and then link them together. This requires some knowledge of mixed language programming, Makefiles, the text user interface (TUI), and is not necessarily very portable. An example using Fortran is given in Section 5.4.1 of the Fluent UDF Manual (version 6.3).<br />
<br />
==== Which compilers work? ====<br />
On Unix-like machines, GCC is the compiler of choice. On Windows machines, Microsoft Visual C++ is the compiler of choice (GCC may also work on Windows- if anyone has firsthand knowledge of this, please share). The free Express Edition of the Microsoft compiler also works.<br />
<br />
==== My UDF won't interpret or compile - what is wrong? ====<br />
The answer depends upon what exactly has happened. <br />
<br />
*If Fluent complains about not being able to find a compiler, then check to make sure that the compiler is properly installed. On Windows machines, it is possible to install the Visual C++ compiler without fully setting up the command line compiler (which Fluent needs to be able to find). During the installation process, you need to select the "register environment variables" option. Failure to do so will likely lead to complaints about things being "not recognized as an internal or external command, operable program or batch file" or missing DLL's. It is theoretically possible to fix this issue by setting the appropriate environment variables, but keep in mind that even when nmake can be found there still may be DLL issues. The easy path is probably reinstallation of Visual Studio (taking special care to make sure that the command line interface is set up properly), but the reinstallation path is always perilous. If you have long-term experience using Windows you should probably know the risks, and if you don't you should consult an expert.<br />
<br />
*If you are interpreting, keep in mind that not everything that is supported for compiled UDF's is supported for interpreted UDF's. This is true both for the UDF interface and the C language. If you are doing something pretty involved and it fails inexplicably, try compiling to see if that makes a difference.<br />
<br />
*There is also the possibility of coding errors. Keep in mind that your source code gets run through the C preprocessor (to change the Fluent macros into C code), so unintended interactions are very possible.<br />
<br />
==== Why do I get the message "'nmake' is not recognized as an internal or external command, operable program or batch file"? ====<br />
This is a Windows/Visual Studio issue. In order to compile your UDF, Fluent needs to know where the nmake program is located, and it currently can't find it. If you open up a command window and enter "nmake", you should probably get the same message. See the previous question/answer.<br />
<br />
==== My UDF interprets/compiles but fails to execute - what is wrong? ====<br />
This commonly occurs due to a faulty operation of some kind. For example, user-defined memory (UDM) is not allocated until initialization, so attempting to access a UDM variable before initialization can lead to a segmentation fault. Try to isolate the cause, and then look for places where your expectation of what is available may not match reality. Finally, keep in mind that if you do something really bad, you may need to restart Fluent before even a fixed UDF will work.<br />
<br />
=== Journal File and Text User Interface (TUI) Related ===<br />
==== What is the Text User Interface? ====<br />
The Text User Interface (TUI) is a command-line-like interface to Fluent. The TUI is accessed through the main Fluent (hit enter while in the main Fluent window), with a menu system and the ability to execute Scheme programs. Fluent's documentation compares the menu system to the UNIX directory structure. Since it is text base, you can create and modify sequences of TUI commands using a simple text editor (see journal files below).<br />
<br />
When Fluent starts, you are in the "root" menu: press enter and you'll see something like this:<br />
<pre><br />
><br />
adapt/ file/ report/<br />
define/ grid/ solve/<br />
display/ parallel/ surface/<br />
exit plot/ view/<br />
</pre><br />
To access the plot menu, just type in "plot" and then press enter. To bring up the available commands, press enter again:<br />
<pre><br />
> plot<br />
<br />
/plot> <br />
change-fft-ref-pressure file-set/ residuals<br />
circum-avg-axial flamelet-curves residuals-set/<br />
circum-avg-radial histogram solution<br />
fft histogram-set/ solution-set/<br />
file plot<br />
file-list plot-direction<br />
</pre><br />
<br />
To exit a menu, simply type "q" and press enter (the rough equivalent of "cd .." in Unix). The TUI also understands command abreviations, so "pl/rs" is interpreted as "plot/residuals-set".<br />
<br />
==== What is a journal file? ====<br />
A journal file is a series of TUI commands stored in a text file. The file can be written in a text editor or generated by Fluent as a transcript of the commands given to Fluent during your session. A journal file generated by Fluent will include any GUI operations (in a TUI form, though). This is quite useful if you have a series of tasks that you need to execute, as it provides a shortcut. To record a journal file, start recording with File -> Write -> Start Journal..., perform whatever tasks you need, and then stop recording with File -> Write -> Stop Journal...<br />
<br />
==== How do I add a comment in a journal file? ====<br />
Any line beginning with a ''';''' (semicolon) is treated as a comment.<br />
<br />
==== How do I set boundary conditions? ====<br />
Suppose we have a boundary named "south" that we want to set as a wall. The command is<br />
<pre><br />
/define/boundary-conditions/zone-type south wall<br />
</pre><br />
which sets the zone "south" as a wall. The details (moving wall, etc.) can then be accessed be executing<br />
<pre><br />
/define/boundary-conditions/wall south<br />
</pre><br />
in the text user interface.<br />
<br />
==== How do I write a XY-plot? ====<br />
look at<br />
http://www.cfd-online.com/Forum/fluent_archive.cgi?read=40200<br />
<br />
==== How do I set material properties? ====<br />
look at http://www.cfd-online.com/Forum/fluent_archive.cgi?read=38768<br />
<br />
one example:<br />
<br />
<pre><br />
//define/materials/delete<br />
air_50c<br />
//define/materials/delete<br />
air_1bar<br />
//define/materials/change-create<br />
air<br />
air_1bar<br />
y<br />
incompressible-ideal-gas<br />
y<br />
piecewise-linear<br />
2<br />
298.15<br />
1007<br />
323.15<br />
1008<br />
y<br />
piecewise-linear<br />
2<br />
298.15<br />
0.02606<br />
323.15<br />
0.02788<br />
y<br />
piecewise-linear<br />
2<br />
273.15<br />
1.72E-05<br />
433.15<br />
2.45E-05<br />
n<br />
n<br />
n<br />
n<br />
n<br />
n<br />
y<br />
</pre><br />
<br />
==== How do I generate a hardcopy of a window? ====<br />
<br />
<pre><br />
display set-window 1 ; if window nr. 1 is the window you want to be hardcopied<br />
//display/set/windows/scale/form ; setting the options for the graph (colourmap)<br />
"%0.2f"<br />
//display/set/color-ramp<br />
bgr<br />
//display/set/hardcopy/color ; setting the options for the window<<br />
color<br />
//display/set/hardcopy/driver<br />
tiff<br />
//display/set/hardcopy/y-res<br />
2400<br />
//display/set/hardcopy/x-res<br />
3106<br />
//display/set/hardcopy/inv<br />
no<br />
//display/hard<br />
filename.tiff<br />
//display/set/hardcopy/inv<br />
yes<br />
//display/hard<br />
filename_inv.tiff<br />
</pre><br />
<br />
==== How do I run multiple cases in batch mode? ====<br />
This could be achieved by running it from journal file. The example journal file that runs two cases is given as:<br />
<pre><br />
file read-case-data xxx1.cas<br />
solve dual-time-iterate yyy1<br />
file write-case-data zzz1.cas<br />
file read-case-data xxx2.cas<br />
yes ; for discard cas dialog<br />
solve dual-time-iterate yyy2<br />
file write-case-data zzz2.cas<br />
</pre><br />
<br />
<br />
Another example:<br />
<pre><br />
rcd filemname.cas<br />
yes<br />
it 10000 <br />
wcd filemname.cas <br />
yes<br />
</pre><br />
<br />
<br />
Have a look at this discussion: [http://www.cfd-online.com/Forum/fluent_archive_2005.cgi/read/32615 http://www.cfd-online.com/Forum/fluent_archive_2005.cgi/read/32615]<br />
<br />
==== How do I loop in a journal file? ====<br />
The best way to loop in a journal file (or the text user interface) is to use one of the Scheme programming language's looping constructs.<br />
<br />
=== Tips === <br />
==== How do I merge two mesh files into one mesh file? ====<br />
To merge two mesh files the suggested utility is tmerge. The syntax of tmerge is simple.<br><br />
<i>utility tmerge -3d file1 file2 finalfile </i> <br><br />
To join the two interior faces use: <br><br />
<i>Grid->Fuse</i> <br><br />
from the menu with Fluent.<br />
<br />
==== How do I export Fieldview data for postprocessing during iterations? ====<br />
<br />
This could be done with the help of menu <b>solve->Execute Commands </b>. <br />
Here are two examples:<br />
<br />
'''Steady Case'''<br />
<br />
<pre><br />
file/export/fug/File_grid-%n<br />
file/export/fud/File_data-%n pressure velocity-magnitude x-velocity y-velocity z-velocity () </pre><br />
<br />
'''Unsteady Case'''<br />
<br />
<pre><br />
file/export/fug/File_grid-%t<br />
file/export/fud/File_data-%t pressure velocity-magnitude x-velocity y-velocity z-velocity () </pre><br />
<br />
You can chose the frequency of export from the <b>Execute Command</b> panel.<br />
<br />
==== What does abbreviation X mean?====<br />
<br />
{| border="1"<br />
|- <br />
| APG || adverse pressure gradient<br />
|- <br />
| BC || Boundary Conditions<br />
|- <br />
| B-L || Boundary Layer<br />
|-<br />
| CFD || Computational Fluid Dynamics<br />
|-<br />
| DES || Detached Eddy Simulation<br />
|-<br />
| DPM || Discrete Phase Model<br />
|-<br />
| FDM || Finite Difference Method<br />
|-<br />
| FEM || Finite Element Method<br />
|-<br />
| FVM || Finite Volume Method<br />
|-<br />
| GUI || Graphical User Interface<br />
|-<br />
| LES || Large Eddy Simulation<br />
|-<br />
| MUSCL || Monotone Upstream-centered Scheme for Conservation Laws<br />
|-<br />
| PDF || Probability Density Function<br />
|-<br />
| QUICK || Quadratic Upstream Interpolation for Convective Kinematics<br />
|-<br />
| RANS || Reynolds Averaged Navier-Stokes<br />
|-<br />
| RSM || Reynolds Stress Model<br />
|-<br />
| SIMPLE || Semi-Implicit Method for the Pressure-Linked Equation<br />
|-<br />
| SST || Shear Stress Transport<br />
|-<br />
| TUI || Text User Interface<br />
|-<br />
| UDF || User defined function<br />
|-<br />
| URF || Under Relaxation Factor<br />
|-<br />
| VOF || Volume Of Fluid<br />
|}<br />
<br />
==== What is the difference between FE and FV?====<br />
<br />
See the answer in the [[General CFD FAQ#What is the difference between FEM, FVM and FDM?|General CFD FAQ]].<br />
<br />
== FloWizard==<br />
<br />
== FIDAP==<br />
<br />
== POLYFLOW ==<br />
<br />
== Gambit ==<br />
===Why does Gambit refuse to open my .dbs file and say that my file is already open? I get an error message - ERROR: IDENTIFIER "X" CURRENTLY OPEN.===<br />
Before opening your file "X.dbs", Gambit looks for a file named "X.lok" to determine the status of your file. If it finds the .lok file, you'll get the above error message (or something like it). If you are in a multi-user environment, you should check that it is not actually already open elsewhere, but in other situations the most likely reason that there is still a X.lok file is that Gambit encountered a problem the last time X.dbs was open. Deleting the .lok file should solve your problem.<br />
<br />
===Q: Why does Gambit complain about the number of nodes on edges being odd and then refuse to mesh a face?===<br />
<br />
A: It is mathematically impossible to create an all-quad mesh with an odd number of intervals on the outer edge loop. If this is inconvenient for you, you may consider a quad-dominant mesh (mostly quads, with a few triangles), or even an all-triangle mesh. Many users achieved good solutions with triangle surface meshes and prism (wedge) boundary layers.<br />
<br />
===Q: What are these boundary layers things defined in Gambit? Do they represent the real situation?===<br />
<br />
A: Gambit's boundary layers allow you to generate specific semi-structured grids topologies on faces that grow out from an edge or edges. You can specify the initial cell height, the growth rate, and a transition pattern that changes the edge-parallel interval count. There are several default settings, which can affect the quality of boundary layers. For cases with sharp corners, normal and offset smoothing can greatly improve quality. Such smoothing is off by default because it requires significantly more computation time.<br />
<br />
===Q: If my quad face mesh has cells with high skewness or large aspect ratios, the pyramiding procedure used by the tet mesher will frequently lead to failure, why? ===<br />
<br />
A: This is because the triangles on the tops of the pyramids have very high skewnesses which can prevent tet meshing. Consider a quad face with a 10-to-1 aspect ratio. Connect opposite corners to create diagonals. This is the "top view" of the pyramid that would be created on this face. The triangles are very highly skewed. It is recommended that your quad faces bounding a region to be tet-meshed have aspect ratios of 5-to-1 or lower.<br />
<br />
===Q: I'm trying to mesh a geometry but I'm getting this message: “check the skewnesses of you face meshes and make sure the face mesh sizes are not too large in areas of small gaps.” I checked the skewness and it's low enough. ===<br />
<br />
A: Your problem is most likely that you have small gaps where the local surface mesh sizes are much larger than the gap sizes. Refining the surface meshes in those areas is likely to solve the problem.<br />
<br />
===Q: I would like to generate grids for different zones using Gambit. How do I merge them together using Gambit or Tgrid later?===<br />
<br />
A: For a valid conformal mesh, mesh nodes on the faces at the interface of the two parts have to be matching within a tolerance. Then, you can either merge the nodes (using Tgrid) or fuse the zones (using Fluent). If you use Tgrid to merge the duplicate nodes, the resulting surface at the interface will have the boundary type as "wall" which should be changed to "interior" if both sides of the interface have same cell (fluid) zone. Fluent automatically converts the resulting surface after fuse to be of "interior" type if both sides of it has the same cell (fluid) zone. <br />
<br />
Also, if you are not using Tgrid, you need to use tfilter tmerge3d to merge the meshes together before reading them into Fluent. Tgrid does the same when you load multiple mesh files at a time. <br />
<br />
===Q: How do I determine what kind of grid to generate? (I would like to known selection criteria between structured and unstructured mesh.)===<br />
<br />
A: Try this approach - consider the meshing options in this order: Single-Block Structured, Multi-Block Structured, Multi-Block Hybrid/Mixed, Fully Unstructured. Gambit can generate most of the cells types and topologies that Fluent can use (with the notable exception of nonconformal meshes). Here are some guidelines/suggestions:<br />
* If you can generate a single-block structured mesh for your problem, then stop there. There is no need to go further. <br />
* If your solution is having problem around a corner (or the like), try multi-block structured mesh. If you are getting improved solution, then stop there. <br />
* If you still have problems around different part of the corner, try the unstructured mesh, with high density mesh around the corner. Before going to a fully unstructured mesh, try making only the problem region unstructured. If the solution is good, then stop there. <br />
* If one part of the mesh still requires special attention, then you can use Fluent's adaptive unstructured facility to refine the mesh until the solution is acceptable. Ideally, you should still get a mesh independent solution. <br />
* It is very important to be able to control every part of your mesh so that you can get good solution everywhere. This is more difficult with unstructured meshes. <br />
* For many geometries, if you can use a structured mesh you will end up with fewer cells (this is particularly true in three dimensions). It is a good idea to use structured-type meshes in regions that will allow it, and use unstructured meshes everywhere else.<br />
* Don't forget that Fluent can handle prismatic cells. If you have an unstructured surface mesh, Gambit can generate a layer of prismatic cells that will resolve boundary layers without requiring a (fully) structured mesh.<br />
<br />
===Q: How do I run GAMBIT as a batch process?=== <br />
<br />
A: To run Gambit in "batch" mode, prepare a journal file (e.g., "test.jou"), then use the command : gambit test -in test.jou <br />
<br />
=== Q: I am having trouble uniting two volumes, what should I do? ===<br />
<br />
"misclassified graph coedge - probably geometrical problem" <br><br />
-> you can try healing the volumes<br><br />
-> deleting the volume (without lower geometry), healing and uniting the faces, then build the volume again<br />
<br />
===Q: I am trying to move a node to modify the mesh on a face with mouse. Why in y direction I can only move the node discretely by 0.5 or multiples of 0.5? I can move it continuously in x direction and I would like to do so in y as well. Is there some default value to change? ===<br />
<br />
== Other Preprocessing Codes==<br />
=== Gambit Turbo ===<br />
<br />
=== TGrid ===<br />
<br />
== Application specific codes ==<br />
<br />
=== Icepak ===<br />
<br />
=== Airpak ===<br />
<br />
=== MixSim ===<br />
<br />
== Educational codes ==<br />
<br />
=== FlowLab ===<br />
[http://flowlab.fluent.com]<br />
<br />
[[Category: FAQ's]]<br />
<br />
{{stub}}</div>Jasondhttp://www.cfd-online.com/Wiki/Fluent_FAQFluent FAQ2007-06-29T20:12:50Z<p>Jasond: /* My UDF won't interpret or compile - what is wrong? */</p>
<hr />
<div>This section is empty. This is just a suggestion on how to structure it. Please feel free to add questions and answers here!<br />
<br />
== Information ==<br />
<br />
=== Learning Material ===<br />
<br />
====How can I learn Fluent and Gambit?====<br />
<br />
The documentation provided by Fluent is actually quite good, so it is a very good place to start. Fluent also provides tutorials and documentation<br />
on the [http://www.fluentusers.com fluentusers] site, which is open to everyone with a<br />
(full) license. Without a full commercial license, it is possible to use the tutorials given at [http://www.studentfluent.com/ studentfluent], or you may be able to register to use the user services center through other channels (e.g. through the university program). There are also some good tutorials available at [http://instruct1.cit.cornell.edu/courses/fluent/index.htm Cornell].<br />
<br />
== FLUENT ==<br />
=== Solver Related ===<br />
==== What does "floating point error" mean? How can I avoid it? ====<br />
<br />
The floating point error has been reported many times and discussed a lot. Here are some of the answers found in the Fluent Forum:<br />
<br />
From numerical computation view point , the basic operations performed by computer are represented inside computer in what is called floating point numbers. The errors that are either because of invalid numeric computation initiated by user or limitation of machine that is used are floating point errors.<br />
<br />
1)Invalid Operations:- Simplest example is if one uses Newton Raphson root finding method to solve f(x)=0 and for some Nth iteration if we get x = x(N) such that derivative of function f(x), f'(x(N))=0 then formula for calculating next iterate x(N+1) = x(N) - f(x(N))/f'(x(N)) requires division by f'(x(N)) which is zero. Here you get divide by zero type of floating point error.<br />
<br />
2) Over or Underflow:- Another type is having data with either too large or too small magnitude called 'overflow' or 'underflow' respectively.Such data cannot be physically represented on computer for direct processing by arithmetic processing part of Processor. <br />
<br />
3) Rounding off errors :- While rounding off a decimal number , some significant digits are lost which cannot be recovered .<br />
e.g. if we round off 0.1 to integer (not greater than it called 'floor' of the given no.) then it is zero. If this value if further used for computation then it may lead to several errors.<br />
<br />
'''SOLVER AND ITERATION''' -----I think if you set shorter time step, it may be good. Or changing little Under-Relaxiation-Factors, it may be good. In my experience, I set 1/3 Under-Relaxiation-Factors as default.� -----�also lower the values of under relaxation factor and use the coupled implicit solver� -----�Try to change under-relaxation factors and if it is unsteady problem maybe time step is to large.� -----�you can improve the ratio in the solve--control--limits, maybe that can help.� -----�you will need to decrease the Courant number� -----�If you still get the error, initialize the domain with nothing to 'Compute from...' Then click 'init'. Again select the surface from which you want to compute the initial values & iterate. This should work.� -----�Another reason could be a to high courant number - that means, that the steps between two iterations are too large and the change in the results is too large as well (high residuals)�<br />
<br />
'''GRID PROBLEMS''' -----�this error comes when I start scaling grid. in gambit, all my dimension is in mm, when in fluent i convert it in meter using buttone SCALE. after it, when i iterate, about hundred iteration, this error appeared. but when i not scale my drawing to m...and let it be as in gambit..then the iteration is success. -----�hi I think you should check your mesh grid mesh is very high. your problem solve by selection a low mesh.� -----�Your mesh is so heavy that your computers resources are not enough. try to use coarser mesh.�<br />
<br />
'''BOUNDARY CONDITIONS''' -----�In my case I had set a wall boundary condition instead of an axis boundary condition and then FLuent refuses to calculate telling me 'floating point error'.� -----�Your Boudary Conditions do not represent real physis.� -----�wrong boundary condition definition might cause the floating point error. For example setting an internal boundary as interior� -----�Once I had the problem, simulating a 2D chamber with a symmetry BC. I set the symmetry somewhere as �axe symmetric� and the floating point error occur� -----�check the turbulence parameter you set. reduce the turbulence intensity to less that one for first, say 50 iterations.<br />
<br />
'''MULTI PROCESSOR ISSUES''' -----"I've had similar problems recently with floating point errors on a multi processor simulation. The solution for my problem seems to be to run on a single processor, where it runs fine....?�<br />
<br />
'''WRONG INITIATION''' ----- Initiating the case with wrong conditions may lead to floating point error when the iterations start.<br />
<br />
==== What is the difference between the coupled and the segregated solver? ====<br />
In the latest Fluent release,6.3.26 these are referred as density based and pressure based solvers.<br />
<br />
The coupled solver will solve all equations (conservation equations for mass, momentum and energy) simultaneously instead of sequentially (the equations are segregated from one another). You should use the coupled solver when the velocity and pressure are strongly coupled (high pressures and high velocities), but very long calculation times may be required when you use the coupled solver.<br />
<br />
In the coupled solvers, the Species Diffusion Term is always included in the energy equation.<br />
<br />
When you use the segregated solver, FLUENT allows you to specify anisotropic conductivity for solid materials<br />
<br />
From the [http://www.cfd-online.com/Forum/fluent_archive.cgi?read=40127 Fluent forum]:<br />
<br />
Choice of solvers depends heavily on the model being solved. The segregated solver solution is based on the pressure, while the coupled solver solution is based on density. This makes the segregated solver better at low speed flows and the coupled solver better at solving transonic / supersonic cases. I wouldn't recommend the coupled solver at any flows below Mach .4 (until the pressure based coupled solver comes out in the next release of Fluent). I've used the Segregated solver up to Mach 1.5 with great results, but the higher speed, the more mesh dependent you become (because the segregated solver tends to "smooth out" shocks), so you have to pay a lot of attention to your meshing.<br />
<br />
The coupled solver tends to be more stable with the defaults settings. The segregated solver tends to be very sensitive to the allowable limits. When trying to get a solution with the segregated solver, DO NOT increase the turbulent viscosity ratio limit (unless you have a great reason to based on past experience or the physics of your current model truly exceeding that limit, but I've never even heard of that being realistic). Instead limit the pressure and temperature limits to reasonable limits (i.e. Plimits = Pstatic +/- (2 * dynamic pressure), and calculate the appropriate temps). You need to give the solution "room to move" while it reaches a solution, but you don't want to give it enough room where it goes out to some totally impossible numbers, and the limits help prevent this.<br />
<br />
=== Model Related ===<br />
==== What is the turbulent viscosity ratio warning and how can I handle it? ====<br />
The problem can be caused by improper values for the boundary condition turbulence parameters. Check the fluent manual (which is kind of more like a textbook), about modeling turbulence.<br />
<br />
For the case of internal flow, you basically have to consider the physical state of the fluid upon entrance to your control volume. If the fluid is coming into your volume from a fully developed turbulent pipe flow, it will have more turbulent energy than from a stagnant fluid. Think of lots of little vortices, which mostly mix things up, and those all have kinetic energy associated). This energy can be expressed as a nondimensional Intensity (a percentage is used). In addition, a Length parameter is specified.<br />
<br />
==== How can I determine the inputs for a porous media or porous jump from flow versus pressure drop data? ====<br />
If you have pressure drop versus velocity data, you can fit the following equation through the data:<br />
<br />
<math>\Delta P = Av^2 + Bv</math><br />
<br />
where <math>\Delta P</math> is the pressure drop and <math>v</math> is the velocity. The coefficients <math>A</math> and <math>B</math> are related to the Fluent variables for the permeability <math>\alpha</math>, and the pressure coefficient <math>C_2</math> by<br />
<br />
<math>A = \frac{C_2 \rho \Delta n}{2}</math> and <math>B=\frac{\mu}{\alpha}\Delta n</math><br />
<br />
where <math>\Delta n</math> is the thicknes of the medium.<br />
<br />
==== How do I model heat conduction in a composite wall? ====<br />
<br />
==== What pressures should be specified at inlets and outlets for buoyancy flow problems? ====<br />
<br />
what pressures at inlet and outlet should specified in natural convection?<br />
<br />
==== Are there any general guidelines on selecting a turbulence model? ====<br />
<br />
==== How can both turbulent and laminar flow be included in one model? ====<br />
<br />
Depends. Fluent cannot presently compute boundary layer instability and subsequent transition to turbulence using a RANS approach (ke, SST, RSM etc). CFX has a new feature to do this, so perhaps it will be incorporated into Fluent soon as they are both owned by ANSYS.<br />
<br />
You therefore have two options : <br />
<br />
1. If you know the point of transition (like on an aircraft wing) from experimental data or DNS simulations, you can impose laminar flow in some regions by meshing a separate fluid region, and enabling "laminar zone" for this region in boundary settings. That is also useful in heat transfer cases, if for example you have turbulent flow one side of a thermal wall, and natural convection on the other side.<br />
<br />
2. A "near-wall" turbulence approach : Either k-omega, SST, or Low Reynolds k-E (which you have to select from the "Turbulence modelling/expert" menu), will damp turbulence near to the wall, either by empirical damping of turbulent "k" (Low Reynolds k-E) or by full solution of the omega equation on a fine enough mesh (k-omega/SST). If you have flows in small gaps in a larger, turbulent domain, in which large lengthscales of turbulence of course could not be supported, the flow will re-laminarise in a physically sensible (although perhaps not mathematically exact) manner. These models will also MAINTAIN laminar flow in external boundary layers, PROVIDED that you have a fine enough mesh (use the laminar mesh distribution guidelines in Fluent manual, too coarse a mesh will lead to non-physical turbulence generation in the BL). BUT they will maintain this laminar flow and evolution of the laminar profile (in the absence of significant disturbance by separation or impingement at the wall) forever, no spontaneous instability or transition to turbulence will occur. So check the length-based Reynolds numbers of walls where you think there will be undisturbed laminar boundaries, that there is not expected to be spontaneous transition of these BLs.<br />
<br />
==== How to start a 3D simulation with an compressible medium and temperature changes? What is important to consider ====<br />
<br />
<br />
I would do it that way:<br />
<br />
1. solve the flow for incompressible medium, without energy equation. Set the density close to the density, that you expect at the present pressure and temperature. The solution for the flow dosn't has to be completely convergent, but the residuals should be on the way down. <br />
<br />
2. Apply energy equation and compressibility of the gas and set the present pressure with operating condition option. You might do some iteration steps as well. Sometimes they are not necessary<br />
<br />
3. Apply the thermal BC<br />
<br />
=== Solution Methodology === <br />
==== How do I carry out rotating body analysis, eg a rotating sphere or cylinder''' in flo'''w? ====<br />
Rotating cylinder problem ( assume circular ), can be done easily by specifying angular velocity on the cylinder wall. As i observed no need of moving mesh for this case. you need to specify the rotation axis with respect to which your cylinder is rotating.<br />
<br />
==== How do I get better and faster convergence? ====<br />
==== What is the role of under-relaxation parameters? What should be the optimum choice of these parameters? ====<br />
They limit the influence of the previous iteration over the present one. If you choose small values it may prevent oscillations in residuum developing. At the same time the solution may need more time to converge. <br />
Keep the default values as they are given in FLUENT. You can decrease them gradually if necessary. Momentum 0.6, pressure 0.1, k 0.4, eps 0.4, mass source 1, viscosity 1.<br />
<br />
=== User-Defined Function (UDF) Related ===<br />
<br />
==== How do I learn UDF programming? ====<br />
There are not to many tutorials out there on this, probably due to the wide variety of things you can do with the UDF interface. The documentation the Fluent provides is pretty good once you know what you are trying to do (chapter 8 of the UDF manual has examples). UDF programming is easier if you have C programming experience, so it is advisable to learn a little C programming, then do some of the simple cases that Fluent provides, then tackle the problem you really want to solve. <br />
<br />
==== How do I create/build/load a UDF? ====<br />
The simplest way to add a UDF into Fluent is to write your UDF in the C programming language and then use Define -> User-Defined -> Functions to either interpret or compile your UDF. It can then be loaded. Fluent provides good documentation of the UDF interface with numerous examples, so read that before trying too much.<br />
<br />
==== Do I have to use C? ====<br />
Yes and no. To hook your UDF into Fluent, you'll probably have to use one of the DEFINE_* macros that Fluent provides, and this is most easily done using C. However, you can write routines that are used in the routines that are defined with the DEFINE_* macros in other languages and then link them together. This requires some knowledge of mixed language programming, Makefiles, the text user interface (TUI), and is not necessarily very portable.<br />
<br />
==== Which compilers work? ====<br />
On Unix-like machines, GCC is the compiler of choice. On Windows machines, Microsoft Visual C++ is the compiler of choice (GCC may also work on Windows- if anyone has firsthand knowledge of this, please share). The free Express Edition of the Microsoft compiler also works.<br />
<br />
==== My UDF won't interpret or compile - what is wrong? ====<br />
The answer depends upon what exactly has happened. <br />
<br />
*If Fluent complains about not being able to find a compiler, then check to make sure that the compiler is properly installed. On Windows machines, it is possible to install the Visual C++ compiler without fully setting up the command line compiler (which Fluent needs to be able to find). During the installation process, you need to select the "register environment variables" option. Failure to do so will likely lead to complaints about things being "not recognized as an internal or external command, operable program or batch file" or missing DLL's. It is theoretically possible to fix this issue by setting the appropriate environment variables, but keep in mind that even when nmake can be found there still may be DLL issues. The easy path is probably reinstallation of Visual Studio (taking special care to make sure that the command line interface is set up properly), but the reinstallation path is always perilous. If you have long-term experience using Windows you should probably know the risks, and if you don't you should consult an expert.<br />
<br />
*If you are interpreting, keep in mind that not everything that is supported for compiled UDF's is supported for interpreted UDF's. This is true both for the UDF interface and the C language. If you are doing something pretty involved and it fails inexplicably, try compiling to see if that makes a difference.<br />
<br />
*There is also the possibility of coding errors. Keep in mind that your source code gets run through the C preprocessor (to change the Fluent macros into C code), so unintended interactions are very possible.<br />
<br />
==== Why do I get the message "'nmake' is not recognized as an internal or external command, operable program or batch file"? ====<br />
This is a Windows/Visual Studio issue. In order to compile your UDF, Fluent needs to know where the nmake program is located, and it currently can't find it. If you open up a command window and enter "nmake", you should probably get the same message. See the previous question/answer.<br />
<br />
==== My UDF interprets/compiles but fails to execute - what is wrong? ====<br />
This commonly occurs due to a faulty operation of some kind. For example, user-defined memory (UDM) is not allocated until initialization, so attempting to access a UDM variable before initialization can lead to a segmentation fault. Try to isolate the cause, and then look for places where your expectation of what is available may not match reality. Finally, keep in mind that if you do something really bad, you may need to restart Fluent before even a fixed UDF will work.<br />
<br />
=== Journal File and Text User Interface (TUI) Related ===<br />
==== What is the Text User Interface? ====<br />
The Text User Interface (TUI) is a command-line-like interface to Fluent. The TUI is accessed through the main Fluent (hit enter while in the main Fluent window), with a menu system and the ability to execute Scheme programs. Fluent's documentation compares the menu system to the UNIX directory structure. Since it is text base, you can create and modify sequences of TUI commands using a simple text editor (see journal files below).<br />
<br />
When Fluent starts, you are in the "root" menu: press enter and you'll see something like this:<br />
<pre><br />
><br />
adapt/ file/ report/<br />
define/ grid/ solve/<br />
display/ parallel/ surface/<br />
exit plot/ view/<br />
</pre><br />
To access the plot menu, just type in "plot" and then press enter. To bring up the available commands, press enter again:<br />
<pre><br />
> plot<br />
<br />
/plot> <br />
change-fft-ref-pressure file-set/ residuals<br />
circum-avg-axial flamelet-curves residuals-set/<br />
circum-avg-radial histogram solution<br />
fft histogram-set/ solution-set/<br />
file plot<br />
file-list plot-direction<br />
</pre><br />
<br />
To exit a menu, simply type "q" and press enter (the rough equivalent of "cd .." in Unix). The TUI also understands command abreviations, so "pl/rs" is interpreted as "plot/residuals-set".<br />
<br />
==== What is a journal file? ====<br />
A journal file is a series of TUI commands stored in a text file. The file can be written in a text editor or generated by Fluent as a transcript of the commands given to Fluent during your session. A journal file generated by Fluent will include any GUI operations (in a TUI form, though). This is quite useful if you have a series of tasks that you need to execute, as it provides a shortcut. To record a journal file, start recording with File -> Write -> Start Journal..., perform whatever tasks you need, and then stop recording with File -> Write -> Stop Journal...<br />
<br />
==== How do I add a comment in a journal file? ====<br />
Any line beginning with a ''';''' (semicolon) is treated as a comment.<br />
<br />
==== How do I set boundary conditions? ====<br />
Suppose we have a boundary named "south" that we want to set as a wall. The command is<br />
<pre><br />
/define/boundary-conditions/zone-type south wall<br />
</pre><br />
which sets the zone "south" as a wall. The details (moving wall, etc.) can then be accessed be executing<br />
<pre><br />
/define/boundary-conditions/wall south<br />
</pre><br />
in the text user interface.<br />
<br />
==== How do I write a XY-plot? ====<br />
look at<br />
http://www.cfd-online.com/Forum/fluent_archive.cgi?read=40200<br />
<br />
==== How do I set material properties? ====<br />
look at http://www.cfd-online.com/Forum/fluent_archive.cgi?read=38768<br />
<br />
one example:<br />
<br />
<pre><br />
//define/materials/delete<br />
air_50c<br />
//define/materials/delete<br />
air_1bar<br />
//define/materials/change-create<br />
air<br />
air_1bar<br />
y<br />
incompressible-ideal-gas<br />
y<br />
piecewise-linear<br />
2<br />
298.15<br />
1007<br />
323.15<br />
1008<br />
y<br />
piecewise-linear<br />
2<br />
298.15<br />
0.02606<br />
323.15<br />
0.02788<br />
y<br />
piecewise-linear<br />
2<br />
273.15<br />
1.72E-05<br />
433.15<br />
2.45E-05<br />
n<br />
n<br />
n<br />
n<br />
n<br />
n<br />
y<br />
</pre><br />
<br />
==== How do I generate a hardcopy of a window? ====<br />
<br />
<pre><br />
display set-window 1 ; if window nr. 1 is the window you want to be hardcopied<br />
//display/set/windows/scale/form ; setting the options for the graph (colourmap)<br />
"%0.2f"<br />
//display/set/color-ramp<br />
bgr<br />
//display/set/hardcopy/color ; setting the options for the window<<br />
color<br />
//display/set/hardcopy/driver<br />
tiff<br />
//display/set/hardcopy/y-res<br />
2400<br />
//display/set/hardcopy/x-res<br />
3106<br />
//display/set/hardcopy/inv<br />
no<br />
//display/hard<br />
filename.tiff<br />
//display/set/hardcopy/inv<br />
yes<br />
//display/hard<br />
filename_inv.tiff<br />
</pre><br />
<br />
==== How do I run multiple cases in batch mode? ====<br />
This could be achieved by running it from journal file. The example journal file that runs two cases is given as:<br />
<pre><br />
file read-case-data xxx1.cas<br />
solve dual-time-iterate yyy1<br />
file write-case-data zzz1.cas<br />
file read-case-data xxx2.cas<br />
yes ; for discard cas dialog<br />
solve dual-time-iterate yyy2<br />
file write-case-data zzz2.cas<br />
</pre><br />
<br />
<br />
Another example:<br />
<pre><br />
rcd filemname.cas<br />
yes<br />
it 10000 <br />
wcd filemname.cas <br />
yes<br />
</pre><br />
<br />
<br />
Have a look at this discussion: [http://www.cfd-online.com/Forum/fluent_archive_2005.cgi/read/32615 http://www.cfd-online.com/Forum/fluent_archive_2005.cgi/read/32615]<br />
<br />
==== How do I loop in a journal file? ====<br />
The best way to loop in a journal file (or the text user interface) is to use one of the Scheme programming language's looping constructs.<br />
<br />
=== Tips === <br />
==== How do I merge two mesh files into one mesh file? ====<br />
To merge two mesh files the suggested utility is tmerge. The syntax of tmerge is simple.<br><br />
<i>utility tmerge -3d file1 file2 finalfile </i> <br><br />
To join the two interior faces use: <br><br />
<i>Grid->Fuse</i> <br><br />
from the menu with Fluent.<br />
<br />
==== How do I export Fieldview data for postprocessing during iterations? ====<br />
<br />
This could be done with the help of menu <b>solve->Execute Commands </b>. <br />
Here are two examples:<br />
<br />
'''Steady Case'''<br />
<br />
<pre><br />
file/export/fug/File_grid-%n<br />
file/export/fud/File_data-%n pressure velocity-magnitude x-velocity y-velocity z-velocity () </pre><br />
<br />
'''Unsteady Case'''<br />
<br />
<pre><br />
file/export/fug/File_grid-%t<br />
file/export/fud/File_data-%t pressure velocity-magnitude x-velocity y-velocity z-velocity () </pre><br />
<br />
You can chose the frequency of export from the <b>Execute Command</b> panel.<br />
<br />
==== What does abbreviation X mean?====<br />
<br />
{| border="1"<br />
|- <br />
| APG || adverse pressure gradient<br />
|- <br />
| BC || Boundary Conditions<br />
|- <br />
| B-L || Boundary Layer<br />
|-<br />
| CFD || Computational Fluid Dynamics<br />
|-<br />
| DES || Detached Eddy Simulation<br />
|-<br />
| DPM || Discrete Phase Model<br />
|-<br />
| FDM || Finite Difference Method<br />
|-<br />
| FEM || Finite Element Method<br />
|-<br />
| FVM || Finite Volume Method<br />
|-<br />
| GUI || Graphical User Interface<br />
|-<br />
| LES || Large Eddy Simulation<br />
|-<br />
| MUSCL || Monotone Upstream-centered Scheme for Conservation Laws<br />
|-<br />
| PDF || Probability Density Function<br />
|-<br />
| QUICK || Quadratic Upstream Interpolation for Convective Kinematics<br />
|-<br />
| RANS || Reynolds Averaged Navier-Stokes<br />
|-<br />
| RSM || Reynolds Stress Model<br />
|-<br />
| SIMPLE || Semi-Implicit Method for the Pressure-Linked Equation<br />
|-<br />
| SST || Shear Stress Transport<br />
|-<br />
| TUI || Text User Interface<br />
|-<br />
| UDF || User defined function<br />
|-<br />
| URF || Under Relaxation Factor<br />
|-<br />
| VOF || Volume Of Fluid<br />
|}<br />
<br />
==== What is the difference between FE and FV?====<br />
<br />
See the answer in the [[General CFD FAQ#What is the difference between FEM, FVM and FDM?|General CFD FAQ]].<br />
<br />
== FloWizard==<br />
<br />
== FIDAP==<br />
<br />
== POLYFLOW ==<br />
<br />
== Gambit ==<br />
===Why does Gambit refuse to open my .dbs file and say that my file is already open? I get an error message - ERROR: IDENTIFIER "X" CURRENTLY OPEN.===<br />
Before opening your file "X.dbs", Gambit looks for a file named "X.lok" to determine the status of your file. If it finds the .lok file, you'll get the above error message (or something like it). If you are in a multi-user environment, you should check that it is not actually already open elsewhere, but in other situations the most likely reason that there is still a X.lok file is that Gambit encountered a problem the last time X.dbs was open. Deleting the .lok file should solve your problem.<br />
<br />
===Q: Why does Gambit complain about the number of nodes on edges being odd and then refuse to mesh a face?===<br />
<br />
A: It is mathematically impossible to create an all-quad mesh with an odd number of intervals on the outer edge loop. If this is inconvenient for you, you may consider a quad-dominant mesh (mostly quads, with a few triangles), or even an all-triangle mesh. Many users achieved good solutions with triangle surface meshes and prism (wedge) boundary layers.<br />
<br />
===Q: What are these boundary layers things defined in Gambit? Do they represent the real situation?===<br />
<br />
A: Gambit's boundary layers allow you to generate specific semi-structured grids topologies on faces that grow out from an edge or edges. You can specify the initial cell height, the growth rate, and a transition pattern that changes the edge-parallel interval count. There are several default settings, which can affect the quality of boundary layers. For cases with sharp corners, normal and offset smoothing can greatly improve quality. Such smoothing is off by default because it requires significantly more computation time.<br />
<br />
===Q: If my quad face mesh has cells with high skewness or large aspect ratios, the pyramiding procedure used by the tet mesher will frequently lead to failure, why? ===<br />
<br />
A: This is because the triangles on the tops of the pyramids have very high skewnesses which can prevent tet meshing. Consider a quad face with a 10-to-1 aspect ratio. Connect opposite corners to create diagonals. This is the "top view" of the pyramid that would be created on this face. The triangles are very highly skewed. It is recommended that your quad faces bounding a region to be tet-meshed have aspect ratios of 5-to-1 or lower.<br />
<br />
===Q: I'm trying to mesh a geometry but I'm getting this message: “check the skewnesses of you face meshes and make sure the face mesh sizes are not too large in areas of small gaps.” I checked the skewness and it's low enough. ===<br />
<br />
A: Your problem is most likely that you have small gaps where the local surface mesh sizes are much larger than the gap sizes. Refining the surface meshes in those areas is likely to solve the problem.<br />
<br />
===Q: I would like to generate grids for different zones using Gambit. How do I merge them together using Gambit or Tgrid later?===<br />
<br />
A: For a valid conformal mesh, mesh nodes on the faces at the interface of the two parts have to be matching within a tolerance. Then, you can either merge the nodes (using Tgrid) or fuse the zones (using Fluent). If you use Tgrid to merge the duplicate nodes, the resulting surface at the interface will have the boundary type as "wall" which should be changed to "interior" if both sides of the interface have same cell (fluid) zone. Fluent automatically converts the resulting surface after fuse to be of "interior" type if both sides of it has the same cell (fluid) zone. <br />
<br />
Also, if you are not using Tgrid, you need to use tfilter tmerge3d to merge the meshes together before reading them into Fluent. Tgrid does the same when you load multiple mesh files at a time. <br />
<br />
===Q: How do I determine what kind of grid to generate? (I would like to known selection criteria between structured and unstructured mesh.)===<br />
<br />
A: Try this approach - consider the meshing options in this order: Single-Block Structured, Multi-Block Structured, Multi-Block Hybrid/Mixed, Fully Unstructured. Gambit can generate most of the cells types and topologies that Fluent can use (with the notable exception of nonconformal meshes). Here are some guidelines/suggestions:<br />
* If you can generate a single-block structured mesh for your problem, then stop there. There is no need to go further. <br />
* If your solution is having problem around a corner (or the like), try multi-block structured mesh. If you are getting improved solution, then stop there. <br />
* If you still have problems around different part of the corner, try the unstructured mesh, with high density mesh around the corner. Before going to a fully unstructured mesh, try making only the problem region unstructured. If the solution is good, then stop there. <br />
* If one part of the mesh still requires special attention, then you can use Fluent's adaptive unstructured facility to refine the mesh until the solution is acceptable. Ideally, you should still get a mesh independent solution. <br />
* It is very important to be able to control every part of your mesh so that you can get good solution everywhere. This is more difficult with unstructured meshes. <br />
* For many geometries, if you can use a structured mesh you will end up with fewer cells (this is particularly true in three dimensions). It is a good idea to use structured-type meshes in regions that will allow it, and use unstructured meshes everywhere else.<br />
* Don't forget that Fluent can handle prismatic cells. If you have an unstructured surface mesh, Gambit can generate a layer of prismatic cells that will resolve boundary layers without requiring a (fully) structured mesh.<br />
<br />
===Q: How do I run GAMBIT as a batch process?=== <br />
<br />
A: To run Gambit in "batch" mode, prepare a journal file (e.g., "test.jou"), then use the command : gambit test -in test.jou <br />
<br />
=== Q: I am having trouble uniting two volumes, what should I do? ===<br />
<br />
"misclassified graph coedge - probably geometrical problem" <br><br />
-> you can try healing the volumes<br><br />
-> deleting the volume (without lower geometry), healing and uniting the faces, then build the volume again<br />
<br />
===Q: I am trying to move a node to modify the mesh on a face with mouse. Why in y direction I can only move the node discretely by 0.5 or multiples of 0.5? I can move it continuously in x direction and I would like to do so in y as well. Is there some default value to change? ===<br />
<br />
== Other Preprocessing Codes==<br />
=== Gambit Turbo ===<br />
<br />
=== TGrid ===<br />
<br />
== Application specific codes ==<br />
<br />
=== Icepak ===<br />
<br />
=== Airpak ===<br />
<br />
=== MixSim ===<br />
<br />
== Educational codes ==<br />
<br />
=== FlowLab ===<br />
[http://flowlab.fluent.com]<br />
<br />
[[Category: FAQ's]]<br />
<br />
{{stub}}</div>Jasondhttp://www.cfd-online.com/Wiki/Flomerics_FAQFlomerics FAQ2007-06-27T23:33:41Z<p>Jasond: Reverted edits by Sharonmshepard (Talk); changed back to last version by Jola</p>
<hr />
<div>[[Category: FAQ's]]<br />
<br />
{{stub}}</div>Jasondhttp://www.cfd-online.com/Wiki/Main_PageMain Page2007-06-27T23:33:00Z<p>Jasond: /* FAQ's */</p>
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<br />
[[Image:X-43A_(Hyper_-_X)_Mach_7_width_300px.jpg]]<br />
<br />
==[[Baldwin-Lomax model]]==<br />
<br />
The Baldwin-Lomax model is a classical algebraic turbulence model which is suitable for high-speed flows with thin attached boundary-layers, typically present in aerospace and turbomachinery applications. The Baldwin-Lomax model is not suitable for cases with large separated regions and significant curvature/rotation effects... <br />
''[[Baldwin-Lomax model|more]]'' <br />
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''"I consider it the obligation of scientists and intellectuals to ensure that their ideas are made accessible and thus useful to society instead of being mere playthings for specialists." '' --Bjarne Stroustrup, from "Design and Evolution of C++"</div>Jasondhttp://www.cfd-online.com/Wiki/Talk:Flomerics_FAQTalk:Flomerics FAQ2007-06-27T17:17:39Z<p>Jasond: </p>
<hr />
<div>This looks more like advertising than real FAQ's. CFD-Wiki is not the place to advertise your products and people who are writing about codes or products sold by their employer should be very careful to write in an objective way without any bias. --[[User:Jola|Jola]] 14:04, 6 June 2007 (MDT)<br />
<br />
:In my opinion, these questions and answers do not belong in the wiki. These question and answers are not on the use of the code, and I think we should reserve the FAQ's for usage-type questions. --[[User:Jasond|Jasond]] 14:57, 6 June 2007 (MDT)<br />
<br />
::Yes, I agree. It is too close to advertising and thereby directly breaks the [[CFD-Wiki:Policy|CFD-Wiki policies]]. I will remove these questions and answers from this FAQ. I hope Sharon will understand. --[[User:Jola|Jola]] 03:39, 7 June 2007 (MDT)<br />
<br />
If that's the case then I suggest that you take a look at the other vendors who have also posted similar information. I made sure that there were no true advertising type content placed. - Sharon<br />
<br />
:I'm sorry if you are feeling targeted (that was not the intent) - but I don't see what you are talking about. Have other vendors posted advertising? Yes. Have we done our best to keep that from happening? Yes. There is an ongoing discussion about guidelines/rules for the posting of code information (see [[Talk:Codes]] and the forum discussion that begins [http://www.cfd-online.com/Forum/wiki.cgi?read=568 here]). I am not 100% happy with all the info that is currently posted, but this is not my personal wiki, and given the collaborative nature of a wiki, compromise is important. In that spirit, I suggest that you get rid of the question and answer formating, condense what you have (a lot), and post it as a "Flowmerics" page that is linked off of the [[Codes]] page. A significant portion of my objection to what you posted was the Q&A format. --[[User:Jasond|Jasond]] 10:36, 8 June 2007 (MDT)<br />
<br />
I followed the format of other vendors. FAQ, doesn't that mean Frequently Asked Questions? It invites Q&A format. I'll do what I can to make it completely different than anyone else. Also, why was the addition of "Flomercs" removed from the subhead under FAQ? Certainly that can't be considered objectionable. Sharon<br />
<br />
:I really don't know what format you are referring to. The FAQ's here are usage FAQ's. The Flomerics link was removed because there is no content in the Flomerics FAQ right now. If you look at the [[Codes]] page, you'll find a lot of edits have been made to remove commercial wording. The path I outlined above should get you to the point where any editing is to remove wording, as opposed to wholesale deletion.--[[User:Jasond|Jasond]] 20:43, 11 June 2007 (MDT)<br />
<br />
:I agree with Jason that the type of information in the questions/answers that Sharon wrote in the [[Flomerics FAQ]] are more suitable in [[EFD]], [[FLOVENT]] or [[FLOTHERM]] pages linked to from the [[Codes]] page, or perhaps in a separate [[Flomerics]] page. I don't know which FAQ it is that Sharon refers to that contains this type of questions/answers. In any case it is very important that all information added to CFD-Wiki is objective and verifiable truths that your competitors will also agree on. This is especially important when the author is an employee of the company or the products described. Links from the main page should not link to empty pages IMHO. --[[User:Jola|Jola]] 06:19, 12 June 2007 (MDT)<br />
<br />
The current revision of the article appears to be very similar to the version that Jonas removed some time ago. I am somewhat dismayed that this has come up again, especially in light of all of the previous discussion. Unless something is done to address the previous objections, I will remove the text later today. --[[User:Jasond|Jasond]] 11:17, 27 June 2007 (MDT)</div>Jasondhttp://www.cfd-online.com/Wiki/Main_PageMain Page2007-06-23T01:01:02Z<p>Jasond: Reverted edits by Gggg (Talk); changed back to last version by Jola</p>
<hr />
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<br />
[[Image:X-43A_(Hyper_-_X)_Mach_7_width_300px.jpg]]<br />
<br />
==[[Baldwin-Lomax model]]==<br />
<br />
The Baldwin-Lomax model is a classical algebraic turbulence model which is suitable for high-speed flows with thin attached boundary-layers, typically present in aerospace and turbomachinery applications. The Baldwin-Lomax model is not suitable for cases with large separated regions and significant curvature/rotation effects... <br />
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''"I consider it the obligation of scientists and intellectuals to ensure that their ideas are made accessible and thus useful to society instead of being mere playthings for specialists." '' --Bjarne Stroustrup, from "Design and Evolution of C++"</div>Jasondhttp://www.cfd-online.com/Wiki/Talk:Flomerics_FAQTalk:Flomerics FAQ2007-06-12T02:43:51Z<p>Jasond: </p>
<hr />
<div>This looks more like advertising than real FAQ's. CFD-Wiki is not the place to advertise your products and people who are writing about codes or products sold by their employer should be very careful to write in an objective way without any bias. --[[User:Jola|Jola]] 14:04, 6 June 2007 (MDT)<br />
<br />
:In my opinion, these questions and answers do not belong in the wiki. These question and answers are not on the use of the code, and I think we should reserve the FAQ's for usage-type questions. --[[User:Jasond|Jasond]] 14:57, 6 June 2007 (MDT)<br />
<br />
::Yes, I agree. It is too close to advertising and thereby directly breaks the [[CFD-Wiki:Policy|CFD-Wiki policies]]. I will remove these questions and answers from this FAQ. I hope Sharon will understand. --[[User:Jola|Jola]] 03:39, 7 June 2007 (MDT)<br />
<br />
If that's the case then I suggest that you take a look at the other vendors who have also posted similar information. I made sure that there were no true advertising type content placed. - Sharon<br />
<br />
:I'm sorry if you are feeling targeted (that was not the intent) - but I don't see what you are talking about. Have other vendors posted advertising? Yes. Have we done our best to keep that from happening? Yes. There is an ongoing discussion about guidelines/rules for the posting of code information (see [[Talk:Codes]] and the forum discussion that begins [http://www.cfd-online.com/Forum/wiki.cgi?read=568 here]). I am not 100% happy with all the info that is currently posted, but this is not my personal wiki, and given the collaborative nature of a wiki, compromise is important. In that spirit, I suggest that you get rid of the question and answer formating, condense what you have (a lot), and post it as a "Flowmerics" page that is linked off of the [[Codes]] page. A significant portion of my objection to what you posted was the Q&A format. --[[User:Jasond|Jasond]] 10:36, 8 June 2007 (MDT)<br />
<br />
I followed the format of other vendors. FAQ, doesn't that mean Frequently Asked Questions? It invites Q&A format. I'll do what I can to make it completely different than anyone else. Also, why was the addition of "Flomercs" removed from the subhead under FAQ? Certainly that can't be considered objectionable. Sharon<br />
<br />
:I really don't know what format you are referring to. The FAQ's here are usage FAQ's. The Flomerics link was removed because there is no content in the Flomerics FAQ right now. If you look at the [[Codes]] page, you'll find a lot of edits have been made to remove commercial wording. The path I outlined above should get you to the point where any editing is to remove wording, as opposed to wholesale deletion.--[[User:Jasond|Jasond]] 20:43, 11 June 2007 (MDT)</div>Jasondhttp://www.cfd-online.com/Wiki/FAQ%27sFAQ's2007-06-12T01:35:45Z<p>Jasond: </p>
<hr />
<div>;[[General CFD FAQ]]<br />
:An FAQ for general CFD related questions.<br />
<br />
;[[CFD-Wiki:FAQ]]<br />
:FAQ's about CFD-Wiki.<br />
<br />
==Commercial codes==<br />
<br />
;[[Ansys FAQ]]<br />
:An FAQ for the software products sold by Ansys Inc - CFX, ICEM CFD, ...<br />
<br />
;[[CD-adapco FAQ]]<br />
:An FAQ for the software products sold by CD-adapco - STAR-CD, STAR-CCM+, ...<br />
<br />
;[[CFD-ACE FAQ]]<br />
:An FAQ for the software sold by ESI Software - [[CFD-ACE]], [[CFD-GEOM]] ...<br />
<br />
;[[CHAM FAQ]]<br />
:An FAQ for the software sold by CHAM - Phoenics, ...<br />
<br />
;[[Flomerics FAQ]]<br />
:An FAQ for the software products sold by Flomerics - Flotherm, EFD.Pro, EFD.Lab, EFD.V5, FloPCB, FloPACK....<br />
<br />
;[[Fluent FAQ]]<br />
:An FAQ for the software products sold by Fluent Inc - FLUENT, Gambit, Tgrid, POLYFLOW, FloWizard, IcePak, AirPak, ...<br />
<br />
;[[Numeca FAQ]]<br />
:An FAQ for the software sold by Numeca - Fine, HEXPRESS, ...</div>Jasondhttp://www.cfd-online.com/Wiki/CFD-Wiki:Wish_listCFD-Wiki:Wish list2007-06-11T04:21:06Z<p>Jasond: Reverted edits by LukAbr (Talk); changed back to last version by Jasond</p>
<hr />
<div>This is a list of items/articles that need work or need to be added to CFD-Wiki. Add things here that you would like to see, but either don't have time or expertise (or whatever) to do. Right now, there is not much on it, but hopefully we'll add more soon. When adding an item, explain it fully and try to gauge the difficulty of the task. Ideally, new editors will be able to choose a task that fits their interests and available time.<br />
<br />
* Clean up the [[Boussinesq eddy viscosity assumption]]. Do some research (and start a forum discussion) on the Boussinesq eddy viscosity assumption and figure out a good form that will work in the various articles (RANS, LES, etc.). Right now we have a couple of different forms (minus signs mainly). All are acceptable, but a single form used uniformly would be better. This is a medium-sized task.<br />
<br />
* Fill in the [[Reynolds stress model (RSM)|Reynolds stress model]] article. This article has come up several times in forum discussions, and a start has been made. This is a larger task, but a fuller article would be greatly appreciated.<br />
<br />
* A practical introduction to [[level set|level set]], [[marker and cell]] and [[volume of fluid]] methods. These are techniques for managing free surfaces in CFD. Also, fast algorithms for finding the vertex of triangles for drawing the surface are needed.<br />
<br />
* Write/add to introductory articles on numerical methods not currently covered in the Wiki. Examples include:<br />
** Lattice Boltzmann methods<br />
** Finite element methods<br />
** Spectral methods (and related methods)<br />
<br />
* Reorganize and finish up the turbulence article. (Note: this article is being based upon the text donated by Prof. Bill George.)<br />
<br />
* Add to the FAQ articles - new questions or answers (ideally both!). Questions that come up again and again in the forums should be added to the appropriate article.</div>Jasondhttp://www.cfd-online.com/Wiki/Talk:RNG_k-epsilon_modelTalk:RNG k-epsilon model2007-06-08T17:00:55Z<p>Jasond: </p>
<hr />
<div>Hello I'm quite new in CFD<br />
<br />
I'm reading about turbulence models and y+...<br />
<br />
What does RNG mean?<br />
<br />
I know that the difference between K-epsilon and RNG k-epsilon models are the constants in the transport equations but what is the purpose to change these variables and when we used each model?<br />
<br />
<br />
Thanks<br />
<br />
:RNG means Renormalization Group Theory. It is a mathematical theory which can be used to derive a turbulence model which is similar to the k-epsilon model. When this was first done it was a kind of revolution that a mathematical theory could be used to derive this kind of turbulence model. It was done by Yakhot and Orzag. The exact formulation and constants in the RNG k-epsilon model is not the same as in the old k-epsilon models though. The RNG models have not been that much of a revolution though and they are not that frequently used today. Some people claim that for rotating flows RNG models are superior. I have tested a RNG k-epsilon model a few times and the only application where I noticed better results with it was in rotating cavities, but then it turned out to be more interesting to run transient and even DES/LES simulations. --[[User:Jola|Jola]] 03:33, 7 June 2007 (MDT)<br />
<br />
The RNG model was developed using Re-Normalisation Group (RNG) methods to renormalise the N-S equations, to account for the effects of smaller scales of motion - in the stadard k-e model the eddy viscosity is determined from a single turbulence length scale, so the calculated turbulent diffusion is that which occurs only at the specified scale, whereas in reality all scales of motion will contribute to the turbulent diffusion. The modified production of the dissipation rate attempts to account for the contribution from other scales of motion. For a reference see {{reference-paper|author=Yakhot, V., Orszag, S.A., Thangam, S., Gatski, T.B. & Speziale, C.G.|year=1992|title=Development of turbulence models for shear flows by a double expansion technique|rest=Physics of Fluids A, Vol. 4, No. 7, pp1510-1520}}. I think the RNG model gave better results for turb flow over a backward facing step - discussed in the paper. I've tried it for modelling vortex evolution which is quite tricky due to the strong rotation and didnt see any better performance than with the standard k-e model. --[[User:Si|Si]] 03:47, 7 June 2007 (MDT)<br />
<br />
::This may be a little late in coming, but isn't this (the above two paragraphs) exactly what the main article needs? Could someone reformat this and move it to the main article? Incidentally, the RNG k-epsilon model is apparently favored for indoor air simulations - just found that out recently (have a ref if there is interest). --[[User:Jasond|Jasond]] 11:00, 8 June 2007 (MDT)</div>Jasondhttp://www.cfd-online.com/Wiki/Talk:CodesTalk:Codes2007-06-08T16:54:31Z<p>Jasond: </p>
<hr />
<div>I added a short note at the top of this page about limiting the length of the code descriptions - this is the result of a discussion in the wiki forum late last year - and I added a link to the copyright page to hopefully head off any more submissions of copyrighted material. I haven't started to look to hard at the individual pages yet - I'll start that later this week. Finally, I have removed all of the links to nonexistent pages in the free solvers section. I'm not sure how that looks. Any opinions? --[[User:Jasond|Jasond]] 15:48, 6 June 2007 (MDT)<br />
<br />
:It looks great I think. It is very good that someone works on the code section. It is one of the most frequented sections. About the description of the codes. What I think is most important is that we never accept any advertisements in these descriptions. Everything should be verifiable and objective truths. Hence, just writing that a code is accurate and uses state-of-the-art models and numerics is not good. Describing which models and methods that are used should be okay though, as long as adjectives like "good", "accurate", "best" etc. are used very sparingly. About the copyright issue. We must of course ensure that we don't break any copyrights. However, I don't think that companies will have any problems with using their descriptions of their codes, on the opposite, that is probably what they want. Some descriptions have also been written by the code companies themselves. For example, the [[Gridgen]] description was written by John Chawner and Rick Matus, two of the top people in Pointwise. It is really not that good that companies themselves write these decriptions since that has a tendency to always produce advertising material. Pointwise have been very good at avoiding advertisements and unverifiable adjectives though. --[[User:Jola|Jola]] 03:22, 7 June 2007 (MDT)<br />
<br />
::I guess that I generally agree. However, the webpage copying looks to be more widespread than I initially thought. I would rather have no description pages at all than have pages that are cut-and-paste jobs. On the [[Gridgen]] page, I guess my objection is that it is rather long - and they have their own web presence for that sort of thing. It does fit your requirements, though, and maybe we should add the part about "verifiable and objective truths" to the text on the code page. --[[User:Jasond|Jasond]] 13:55, 7 June 2007 (MDT)<br />
<br />
:::Yes, just having cut-and-paste copies of web-sites that can just as well be linked to directly is not good. We will just have old data that takes time to maintain and gives nothing extra. And just as you talked about if the original authors are not aware of it we will also break their copyrights. I think that you have started a good job of cleaning this section up. I will try to add something about the CFD-Wiki policies and the "verifiable and objective truths" requirement unless you or someone else have done it tomorrow. Now I have to go to bed, it is running late over here in Sweden --[[User:Jola|Jola]] 15:46, 7 June 2007 (MDT)<br />
<br />
::::As of right now, there are only a few issues left (as far as I know): [[Delaundo]]- which is a public domain code (so I left the text as is even though it is cut-and-pasted), [[vtk]],[[vtk.Net]] - Tony posted these but does give specific attribution, and there are a few pages that are basically nothing. I leave these as is unless there is opinion otherwise. I would still like to shorten the [[Gridgen]] page, but I won't do that unless you specifically agree that it needs to be shortened (and this is the last mention of it from me). I think I'll leave the policy modification to you, but I might add a little more text to my "note to contributors" - I want to keep things reasonable, but I don't want to discourage contribution. For the free codes, it might be a good idea to figure out a way to include license information on the main [[Codes]] page - maybe break the list into a "GPL" list and an "Other free license" list. Wouldn't it also be nice to have some sort of information on the language used? --[[User:Jasond|Jasond]] 10:54, 8 June 2007 (MDT)</div>Jasondhttp://www.cfd-online.com/Wiki/CodesCodes2007-06-08T16:39:34Z<p>Jasond: /* Solvers */</p>
<hr />
<div>An overview of both free and commercial CFD software. Here you will find short descriptions of codes along with links to resources.<br />
<br />
Note to contributers: Please try to keep descriptions short and to the point (approximately 200 words) and avoid long lists of features or capabilities. Also keep in mind that all contributions are considered to be released under the GNU Free Documentation License 1.2 (see [[Project:Copyrights]] for details). <br />
<br />
== Free codes ==<br />
<br />
This section lists codes that are in the public domain, and codes that are available under GPL, BSD or similar licenses.<br />
<br />
=== Solvers ===<br />
<br />
* ADFC -- [http://adfc.sourceforge.net/index.html ADFC homepage]<br />
* Diagonalized Upwind Navier Stokes -- [http://duns.sourceforge.net DUNS homepage]<br />
* Dolfyn -- [http://www.dolfyn.net/dolfyn/index_en.html dolfyn homepage]<br />
*[[Edge]] -- [http://www.edge.foi.se/ Edge homepage]<br />
*[[ELMER]] -- [http://www.csc.fi/elmer/ ELMER homepage]<br />
* Featflow -- [http://www.featflow.de Featflow homepage]<br />
* Femwater -- [http://www.cee.odu.edu/model/femwater.php Femwater code]<br />
* FreeFEM -- [http://www.freefem.org FreeFEM homepage]<br />
*[[Gerris Flow Solver]] -- [http://gfs.sourceforge.net/ Gerris Flow Solver homepage]<br />
* IMTEK Mathematica Supplement (IMS) -- [http://www.imtek.uni-freiburg.de/simulation/mathematica/IMSweb/ IMTEK Mathematica Supplement (IMS) homepage]<br />
* iNavier -- [http://inavier.sourceforge.net/ iNavier Solver Home Page]<br />
* MFIX -- [http://www.mfix.org Computational multiphase flow homepage]<br />
*[[NaSt2D-2.0]] -- [http://home.arcor.de/drklaus.bauerfeind/nast/eNaSt2D.html NaSt2D-2.0 homepage]<br />
*[[NSC2KE]] -- [http://www-rocq1.inria.fr/gamma/cdrom/www/nsc2ke/eng.htm NSC2KE homepage]<br />
*[[OpenFlower]] -- [http://sourceforge.net/projects/openflower/ OpenFlower homepage]<br />
*[[OpenFOAM]] -- [http://www.openfoam.org/ OpenFOAM homepage]<br />
* OpenFVM -- [http://openfvm.sourceforge.net/ OpenFVM homepage]<br />
* PETSc-FEM -- [http://www.cimec.org.ar/petscfem PETSc-FEM homepage]<br />
* PP3D -- [http://www.featflow.de/ parpp3d++ homepage]<br />
* SLFCFD -- [http://slfcfd.sourceforge.net SLFCFD homepage]<br />
*[[SSIIM]] -- [http://folk.ntnu.no/nilsol/cfd/ CFD at NTNU]<br />
*[[Tochnog]] -- [http://tochnog.sourceforge.net Tochnog homepage]<br />
* Typhon solver -- [http://typhon.sf.net Typhon solver homepage]<br />
<br />
=== Grid generation ===<br />
<br />
*[[Delaundo]] -- [http://www.cerfacs.fr/~muller/delaundo.html Delaundo homepage]<br />
* GMSH -- [http://www.geuz.org/gmsh/ GMSH hompage]<br />
* NETGEN -- [http://www.hpfem.jku.at/netgen/ NETGEN homepage]<br />
* SALOME -- [http://www.salome-platform.org SALOME homepage]<br />
* TETGEN -- [http://tetgen.berlios.de/ TETGEN hompage]<br />
*[[Triangle]] -- [http://www.cs.cmu.edu/~quake/triangle.html Triangle homepage]<br />
<br />
=== Visualization ===<br />
*[[DISLIN]] -- [http://www.mps.mpg.de/dislin/server.html DISLIN homepage]<br />
* GMV -- [http://www-xdiv.lanl.gov/XCM/gmv/ GMV homepage]<br />
*[[Gnuplot]] -- [http://www.gnuplot.info/ gnuplot homepage]<br />
* GRI -- [http://gri.sourceforge.net/ GRI homepage]<br />
*[[Mayavi]] -- [http://mayavi.sourceforge.net/ MayaVi homepage]<br />
*[[OpenDX]] -- [http://www.opendx.org OpenDX homepage]<br />
*[[ParaView]] -- [http://www.paraview.org/HTML/Index.html ParaView homepage]<br />
*[[Tioga]] -- [http://www.kitp.ucsb.edu/~paxton/tioga.html Tioga homepage]<br />
*[[Vigie]] -- [http://www-sop.inria.fr/sinus/Softs/vigie.html Vigie homepage]<br />
*[[Visit]] -- [http://www.llnl.gov/visit Visit homepage]<br />
*[[vtk]] -- [http://www.vtk.org vtk homepage]<br />
*[[vtk.Net]] -- [http://vtkdotnet.sourceforge.net/ vtk.Net homepage]<br />
<br />
=== Miscellaneous ===<br />
<br />
*[[Engauge Digitizer]] -- [http://digitizer.sourceforge.net Engauge Digitizer homepage]<br />
*[[Ftnchek]] -- [http://www.dsm.fordham.edu/~ftnchek/ ftnchek homepage]<br />
*[[g3data]] -- [http://www.frantz.fi/software/g3data.php g3data homepage]<br />
* GIFMerge -- [http://www.the-labs.com/GIFMerge/ GIFMerge homepage]<br />
*[[Gifsicle]] -- [http://www.lcdf.org/~eddietwo/gifsicle/ Gifsicle homepage]<br />
*[[ImageMagick]] -- [http://www.imagemagick.org ImageMagick homepage]<br />
<br />
== Commercial codes ==<br />
<br />
=== Solvers ===<br />
<br />
* AcuSolve -- [http://www.acusim.com/ ACUSIM Software's homepage]<br />
* ADINA-F -- [http://www.adina.com/index.html ADINA's homepage]<br />
* ADINA-FSI -- [http://www.adina.com/index.html ADINA's homepage]<br />
* ANSWER -- [http://www.acricfd.com/ ACRi's homepage]<br />
*[http://www.cfd-online.com/W/index.php?title=CFD%2B%2B CFD++] -- [http://www.metacomptech.com Metacomp Techonlogies' homepage]<br />
* CFD2000 -- [http://www.adaptive-research.com/ Adaptive Research's homepage]<br />
*[[CFD-FASTRAN]] -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
* CFD-ACE -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
* CFdesign -- [http://www.cfdesign.com CFdesign's homepage]<br />
* CFX -- [http://www.ansys.com/ Ansys' homepage]<br />
* EFD - Engineering Fluid Dynamics -- [http://www.nika.biz/ Flomerics/NIKA homepage]<br />
*[[FENSAP-ICE]] -- [http://www.newmerical.com/ NTI' homepage]<br />
* FINE -- [http://www.numeca.be/ Numeca's homepage]<br />
* FIRE -- [http://www.avl.com/ AVL's homepage]<br />
*[[FLACS]] -- [http://www.gexcon.com/index.php?src=flacs/overview.html GexCon's homepage]<br />
* FLOW-3D -- [http://www.flow3d.com/ Flow Science's homepage]<br />
* FLOMERICS-- [http://www.flomerics.com Flomerics' homepage]<br />
* FLOWVISION -- [http://www.fv-tech.com FlowVision's homepage]<br />
*[[FLUENT]] -- [http://www.fluent.com Fluent's homepage]<br />
* FluSol -- [http://www.cfd-rocket.com FluSol's hompage]<br />
* Flowz--[http://www.zeusnumerix.com Zeus Numerix's homepage ]<br />
*[[J-FLO]] -- [http://www.newmerical.com NTI's homepage]<br />
* KINetics Reactive Flows -- [http://www.ReactionDesign.com Reaction Design's homepage]<br />
* KIVA--[http://www.lanl.gov/orgs/t/t3/codes/kiva.shtml Los Alamos homepage]<br />
*[[NOGRID FPM]] -- [http://www.no-grid.com NOGRIDS's homepage]<br />
*[[PHOENICS]] -- [http://www.cham.co.uk CHAM's homepage]<br />
*[[SPLASH]] -- [http://www.panix.com/~brosen SPLASH's homepage]<br />
*[[STAR-CD]] -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
* STAR-CCMplus -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
* Turb'Flow -- [http://www.fluorem.com Fluorem's hompage]<br />
<br />
=== Grid generation ===<br />
<br />
* ADINA-AUI -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-GEOM]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFD-VISCART]] -- [http://www.esi-group.com/ ESI's homepage]<br />
* CFDExpert-GridZ --[http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
*[[Gridgen]] -- [http://www.pointwise.com/ Pointwise's homepage]<br />
* GridPro -- [http://www.gridpro.com/ PDC's homepage]<br />
* Harpoon -- [http://www.ensight.com/ CEI's homepage]<br />
* ICEM CFD -- [http://www.ansys.com/ ANSYS' homepage]<br />
<br />
=== Visualization ===<br />
<br />
* ADINA-AUI -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-VIEW]] -- [http://www.esi-group.com/ ESI's homepage]<br />
* CFX-Post -- [http://www.ansys.com/ ANSYS' homepage]<br />
* COVISE -- [http://www.visenso.de/ Visenso's homepage]<br />
* EnSight -- [http://www.ensight.com/ CEI's homepage]<br />
* Fieldview -- [http://www.ilight.com/ Intelligent Light's homepage]<br />
*[[Tecplot]] -- [http://www.tecplot.com/ Tecplot's homepage]<br />
*ViewZ -- [http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
<br />
=== Systems ===<br />
<br />
* ADINA -- [http://www.adina.com/index.html ADINA's homepage]<br />
* Flownex -- [http://www.flownex.com/ Flownex's homepage]<br />
<br />
== Online tools and services ==<br />
<br />
*[[CFDNet]] -- [http://www.cfdnet.com/ CFDNet homepage]</div>Jasondhttp://www.cfd-online.com/Wiki/Talk:Flomerics_FAQTalk:Flomerics FAQ2007-06-08T16:36:15Z<p>Jasond: </p>
<hr />
<div>This looks more like advertising than real FAQ's. CFD-Wiki is not the place to advertise your products and people who are writing about codes or products sold by their employer should be very careful to write in an objective way without any bias. --[[User:Jola|Jola]] 14:04, 6 June 2007 (MDT)<br />
<br />
:In my opinion, these questions and answers do not belong in the wiki. These question and answers are not on the use of the code, and I think we should reserve the FAQ's for usage-type questions. --[[User:Jasond|Jasond]] 14:57, 6 June 2007 (MDT)<br />
<br />
::Yes, I agree. It is too close to advertising and thereby directly breaks the [[CFD-Wiki:Policy|CFD-Wiki policies]]. I will remove these questions and answers from this FAQ. I hope Sharon will understand. --[[User:Jola|Jola]] 03:39, 7 June 2007 (MDT)<br />
<br />
If that's the case then I suggest that you take a look at the other vendors who have also posted similar information. I made sure that there were no true advertising type content placed. - Sharon<br />
<br />
:I'm sorry if you are feeling targeted (that was not the intent) - but I don't see what you are talking about. Have other vendors posted advertising? Yes. Have we done our best to keep that from happening? Yes. There is an ongoing discussion about guidelines/rules for the posting of code information (see [[Talk:Codes]] and the forum discussion that begins [http://www.cfd-online.com/Forum/wiki.cgi?read=568 here]). I am not 100% happy with all the info that is currently posted, but this is not my personal wiki, and given the collaborative nature of a wiki, compromise is important. In that spirit, I suggest that you get rid of the question and answer formating, condense what you have (a lot), and post it as a "Flowmerics" page that is linked off of the [[Codes]] page. A significant portion of my objection to what you posted was the Q&A format. --[[User:Jasond|Jasond]] 10:36, 8 June 2007 (MDT)</div>Jasondhttp://www.cfd-online.com/Wiki/Talk:FAQ%27sTalk:FAQ's2007-06-07T21:03:19Z<p>Jasond: </p>
<hr />
<div>The FAQ's for codes are currently divided according to the company. Perhaps we should change this to instead be a separate FAQ for each code? Now that Ansys owns both CFX, FLUENT and ICEM is isn't very convenient to have an Ansys FAQ which covers all these codes. A code specific FAQ is more convenient to use and will survive consolidation deals when companies bye a code from another company. We can also create FAQ sections for each company that answers general questions and contains links to the specific code FAQ's. What do you think? --[[User:Jola|Jola]] 03:48, 7 June 2007 (MDT)<br />
<br />
: At a glance, it looks like the Ansys FAQ is mainly a CFX FAQ. I think it would probably be more accurate to call it a CFX FAQ - and since there is a CFX forum, it makes more sense also. Other FAQ sections could be added as needed (as usual). --[[User:Jasond|Jasond]] 15:03, 7 June 2007 (MDT)</div>Jasondhttp://www.cfd-online.com/Wiki/FLUENTFLUENT2007-06-07T20:59:03Z<p>Jasond: </p>
<hr />
<div>FLUENT is a commercial CFD code. It is a product of Ansys Inc.<br />
<br />
Current version is 6.3.26. (at May 21, 2007).<br />
<br />
== CFD-Online Resources ==<br />
*[[Fluent FAQ]]<br />
*[http://www.cfd-online.com/Forum/fluent.cgi Fluent Forum]<br />
<br />
== External Link ==<br />
*[http://www.fluent.com Fluent homepage]</div>Jasondhttp://www.cfd-online.com/Wiki/CodesCodes2007-06-07T20:55:15Z<p>Jasond: /* Commercial codes */</p>
<hr />
<div>An overview of both free and commercial CFD software. Here you will find short descriptions of codes along with links to resources.<br />
<br />
Note to contributers: Please try to keep descriptions short and to the point (approximately 200 words) and avoid long lists of features or capabilities. Also keep in mind that all contributions are considered to be released under the GNU Free Documentation License 1.2 (see [[Project:Copyrights]] for details). <br />
<br />
== Free codes ==<br />
<br />
This section lists codes that are in the public domain, and codes that are available under GPL, BSD or similar licenses.<br />
<br />
=== Solvers ===<br />
<br />
* ADFC -- [http://adfc.sourceforge.net/index.html ADFC homepage]<br />
* Diagonalized Upwind Navier Stokes -- [http://duns.sourceforge.net DUNS homepage]<br />
* Dolfyn -- [http://www.dolfyn.net/dolfyn/index_en.html dolfyn homepage]<br />
*[[Edge]] -- [http://www.edge.foi.se/ Edge homepage]<br />
*[[ELMER]] -- [http://www.csc.fi/elmer/ ELMER homepage]<br />
* Featflow -- [http://www.featflow.de Featflow homepage]<br />
* Femwater -- [http://www.cee.odu.edu/model/femwater.php Femwater code]<br />
* FreeFEM -- [http://www.freefem.org FreeFEM homepage]<br />
*[[Gerris Flow Solver]] -- [http://gfs.sourceforge.net/ Gerris Flow Solver homepage]<br />
* IMTEK Mathematica Supplement (IMS) -- [http://www.imtek.uni-freiburg.de/simulation/mathematica/IMSweb/ IMTEK Mathematica Supplement (IMS) homepage]<br />
* iNavier -- [http://inavier.sourceforge.net/ iNavier Solver Home Page]<br />
* MFIX -- [http://www.mfix.org Computational multiphase flow homepage]<br />
*[[NaSt2D-2.0]] -- [http://home.arcor.de/drklaus.bauerfeind/nast/eNaSt2D.html NaSt2D-2.0 homepage]<br />
*[[NSC2KE]] -- [http://www-rocq1.inria.fr/gamma/cdrom/www/nsc2ke/eng.htm NSC2KE homepage]<br />
*[[OpenFlower]] -- [http://sourceforge.net/projects/openflower/ OpenFlower homepage]<br />
*[[OpenFOAM]] -- [http://www.openfoam.org/ OpenFOAM homepage]<br />
* OpenFVM -- [http://openfvm.sourceforge.net/ OpenFVM homepage]<br />
* PETSc-FEM -- [http://www.cimec.org.ar/petscfem PETSc-FEM homepage]<br />
* PP3D -- [http://www.featflow.de/ parpp3d++ homepage]<br />
* SLFCFD -- [http://slfcfd.sourceforge.net SLFCFD homepage]<br />
*[[SSIIM]] -- [http://folk.ntnu.no/nilsol/cfd/ CFD at NTNU]<br />
*[[Tochnog]] -- [http://tochnog.sourceforge.net Tochnog homepage]<br />
* Typhon solver -- [http://typhon.sf.net Typhon solver homepage]<br />
<br />
=== Grid generation ===<br />
<br />
*[[Delaundo]] -- [http://www.cerfacs.fr/~muller/delaundo.html Delaundo homepage]<br />
* GMSH -- [http://www.geuz.org/gmsh/ GMSH hompage]<br />
* NETGEN -- [http://www.hpfem.jku.at/netgen/ NETGEN homepage]<br />
* SALOME -- [http://www.salome-platform.org SALOME homepage]<br />
* TETGEN -- [http://tetgen.berlios.de/ TETGEN hompage]<br />
*[[Triangle]] -- [http://www.cs.cmu.edu/~quake/triangle.html Triangle homepage]<br />
<br />
=== Visualization ===<br />
*[[DISLIN]] -- [http://www.mps.mpg.de/dislin/server.html DISLIN homepage]<br />
* GMV -- [http://www-xdiv.lanl.gov/XCM/gmv/ GMV homepage]<br />
*[[Gnuplot]] -- [http://www.gnuplot.info/ gnuplot homepage]<br />
* GRI -- [http://gri.sourceforge.net/ GRI homepage]<br />
*[[Mayavi]] -- [http://mayavi.sourceforge.net/ MayaVi homepage]<br />
*[[OpenDX]] -- [http://www.opendx.org OpenDX homepage]<br />
*[[ParaView]] -- [http://www.paraview.org/HTML/Index.html ParaView homepage]<br />
*[[Tioga]] -- [http://www.kitp.ucsb.edu/~paxton/tioga.html Tioga homepage]<br />
*[[Vigie]] -- [http://www-sop.inria.fr/sinus/Softs/vigie.html Vigie homepage]<br />
*[[Visit]] -- [http://www.llnl.gov/visit Visit homepage]<br />
*[[vtk]] -- [http://www.vtk.org vtk homepage]<br />
*[[vtk.Net]] -- [http://vtkdotnet.sourceforge.net/ vtk.Net homepage]<br />
<br />
=== Miscellaneous ===<br />
<br />
*[[Engauge Digitizer]] -- [http://digitizer.sourceforge.net Engauge Digitizer homepage]<br />
*[[Ftnchek]] -- [http://www.dsm.fordham.edu/~ftnchek/ ftnchek homepage]<br />
*[[g3data]] -- [http://www.frantz.fi/software/g3data.php g3data homepage]<br />
* GIFMerge -- [http://www.the-labs.com/GIFMerge/ GIFMerge homepage]<br />
*[[Gifsicle]] -- [http://www.lcdf.org/~eddietwo/gifsicle/ Gifsicle homepage]<br />
*[[ImageMagick]] -- [http://www.imagemagick.org ImageMagick homepage]<br />
<br />
== Commercial codes ==<br />
<br />
=== Solvers ===<br />
<br />
* AcuSolve -- [http://www.acusim.com/ ACUSIM Software's homepage]<br />
* ADINA-F -- [http://www.adina.com/index.html ADINA's homepage]<br />
* ADINA-FSI -- [http://www.adina.com/index.html ADINA's homepage]<br />
* ANSWER -- [http://www.acricfd.com/ ACRi's homepage]<br />
*[http://www.cfd-online.com/W/index.php?title=CFD%2B%2B CFD++] -- [http://www.metacomptech.com Metacomp Techonlogies' homepage]<br />
* CFD2000 -- [http://www.adaptive-research.com/ Adaptive Research's homepage]<br />
*[[CFD-FASTRAN]] -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
* CFD-ACE -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
* CFdesign -- [http://www.cfdesign.com CFdesign's homepage]<br />
* CFX -- [http://www.ansys.com/ Ansys' homepage]<br />
* EFD - Engineering Fluid Dynamics -- [http://www.nika.biz/ Flomerics/NIKA homepage]<br />
*[[FENSAP-ICE]] -- [http://www.newmerical.com/ NTI' homepage]<br />
* FINE -- [http://www.numeca.be/ Numeca's homepage]<br />
* FIRE -- [http://www.avl.com/ AVL's homepage]<br />
*[[FLACS]] -- [http://www.gexcon.com/index.php?src=flacs/overview.html GexCon's homepage]<br />
* FLOW-3D -- [http://www.flow3d.com/ Flow Science's homepage]<br />
* FLOMERICS-- [http://www.flomerics.com Flomerics' homepage]<br />
* FLOWVISION -- [http://www.fv-tech.com FlowVision's homepage]<br />
*[[FLUENT]] -- [http://www.fluent.com Fluent's homepage]<br />
* FluSol -- [http://www.cfd-rocket.com FluSol's hompage]*[[J-FLO]] -- [http://www.newmerical.com NTI's homepage]<br />
* Flowz--[http://www.zeusnumerix.com Zeus Numerix's homepage ]<br />
* KINetics Reactive Flows -- [http://www.ReactionDesign.com Reaction Design's homepage]<br />
* KIVA--[http://www.lanl.gov/orgs/t/t3/codes/kiva.shtml Los Alamos homepage]<br />
*[[NOGRID FPM]] -- [http://www.no-grid.com NOGRIDS's homepage]<br />
*[[PHOENICS]] -- [http://www.cham.co.uk CHAM's homepage]<br />
*[[SPLASH]] -- [http://www.panix.com/~brosen SPLASH's homepage]<br />
*[[STAR-CD]] -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
* STAR-CCMplus -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
* Turb'Flow -- [http://www.fluorem.com Fluorem's hompage]<br />
<br />
=== Grid generation ===<br />
<br />
* ADINA-AUI -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-GEOM]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFD-VISCART]] -- [http://www.esi-group.com/ ESI's homepage]<br />
* CFDExpert-GridZ --[http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
*[[Gridgen]] -- [http://www.pointwise.com/ Pointwise's homepage]<br />
* GridPro -- [http://www.gridpro.com/ PDC's homepage]<br />
* Harpoon -- [http://www.ensight.com/ CEI's homepage]<br />
* ICEM CFD -- [http://www.ansys.com/ ANSYS' homepage]<br />
<br />
=== Visualization ===<br />
<br />
* ADINA-AUI -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-VIEW]] -- [http://www.esi-group.com/ ESI's homepage]<br />
* CFX-Post -- [http://www.ansys.com/ ANSYS' homepage]<br />
* COVISE -- [http://www.visenso.de/ Visenso's homepage]<br />
* EnSight -- [http://www.ensight.com/ CEI's homepage]<br />
* Fieldview -- [http://www.ilight.com/ Intelligent Light's homepage]<br />
*[[Tecplot]] -- [http://www.tecplot.com/ Tecplot's homepage]<br />
*ViewZ -- [http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
<br />
=== Systems ===<br />
<br />
* ADINA -- [http://www.adina.com/index.html ADINA's homepage]<br />
* Flownex -- [http://www.flownex.com/ Flownex's homepage]<br />
<br />
== Online tools and services ==<br />
<br />
*[[CFDNet]] -- [http://www.cfdnet.com/ CFDNet homepage]</div>Jasondhttp://www.cfd-online.com/Wiki/GifsicleGifsicle2007-06-07T20:48:04Z<p>Jasond: Removed text that had been copied from the website</p>
<hr />
<div>Gifsicle is a freely available command-line tool for the manipulation of GIF images. It is written in C, and is available under the terms of the GNU GPL. Precompiled executables are available for a number of different platforms.<br />
<br />
==External Link==<br />
*[http://www.lcdf.org/~eddietwo/gifsicle/ Gifsicle homepage]</div>Jasondhttp://www.cfd-online.com/Wiki/CodesCodes2007-06-07T20:43:04Z<p>Jasond: /* Miscellaneous */</p>
<hr />
<div>An overview of both free and commercial CFD software. Here you will find short descriptions of codes along with links to resources.<br />
<br />
Note to contributers: Please try to keep descriptions short and to the point (approximately 200 words) and avoid long lists of features or capabilities. Also keep in mind that all contributions are considered to be released under the GNU Free Documentation License 1.2 (see [[Project:Copyrights]] for details). <br />
<br />
== Free codes ==<br />
<br />
This section lists codes that are in the public domain, and codes that are available under GPL, BSD or similar licenses.<br />
<br />
=== Solvers ===<br />
<br />
* ADFC -- [http://adfc.sourceforge.net/index.html ADFC homepage]<br />
* Diagonalized Upwind Navier Stokes -- [http://duns.sourceforge.net DUNS homepage]<br />
* Dolfyn -- [http://www.dolfyn.net/dolfyn/index_en.html dolfyn homepage]<br />
*[[Edge]] -- [http://www.edge.foi.se/ Edge homepage]<br />
*[[ELMER]] -- [http://www.csc.fi/elmer/ ELMER homepage]<br />
* Featflow -- [http://www.featflow.de Featflow homepage]<br />
* Femwater -- [http://www.cee.odu.edu/model/femwater.php Femwater code]<br />
* FreeFEM -- [http://www.freefem.org FreeFEM homepage]<br />
*[[Gerris Flow Solver]] -- [http://gfs.sourceforge.net/ Gerris Flow Solver homepage]<br />
* IMTEK Mathematica Supplement (IMS) -- [http://www.imtek.uni-freiburg.de/simulation/mathematica/IMSweb/ IMTEK Mathematica Supplement (IMS) homepage]<br />
* iNavier -- [http://inavier.sourceforge.net/ iNavier Solver Home Page]<br />
* MFIX -- [http://www.mfix.org Computational multiphase flow homepage]<br />
*[[NaSt2D-2.0]] -- [http://home.arcor.de/drklaus.bauerfeind/nast/eNaSt2D.html NaSt2D-2.0 homepage]<br />
*[[NSC2KE]] -- [http://www-rocq1.inria.fr/gamma/cdrom/www/nsc2ke/eng.htm NSC2KE homepage]<br />
*[[OpenFlower]] -- [http://sourceforge.net/projects/openflower/ OpenFlower homepage]<br />
*[[OpenFOAM]] -- [http://www.openfoam.org/ OpenFOAM homepage]<br />
* OpenFVM -- [http://openfvm.sourceforge.net/ OpenFVM homepage]<br />
* PETSc-FEM -- [http://www.cimec.org.ar/petscfem PETSc-FEM homepage]<br />
* PP3D -- [http://www.featflow.de/ parpp3d++ homepage]<br />
* SLFCFD -- [http://slfcfd.sourceforge.net SLFCFD homepage]<br />
*[[SSIIM]] -- [http://folk.ntnu.no/nilsol/cfd/ CFD at NTNU]<br />
*[[Tochnog]] -- [http://tochnog.sourceforge.net Tochnog homepage]<br />
* Typhon solver -- [http://typhon.sf.net Typhon solver homepage]<br />
<br />
=== Grid generation ===<br />
<br />
*[[Delaundo]] -- [http://www.cerfacs.fr/~muller/delaundo.html Delaundo homepage]<br />
* GMSH -- [http://www.geuz.org/gmsh/ GMSH hompage]<br />
* NETGEN -- [http://www.hpfem.jku.at/netgen/ NETGEN homepage]<br />
* SALOME -- [http://www.salome-platform.org SALOME homepage]<br />
* TETGEN -- [http://tetgen.berlios.de/ TETGEN hompage]<br />
*[[Triangle]] -- [http://www.cs.cmu.edu/~quake/triangle.html Triangle homepage]<br />
<br />
=== Visualization ===<br />
*[[DISLIN]] -- [http://www.mps.mpg.de/dislin/server.html DISLIN homepage]<br />
* GMV -- [http://www-xdiv.lanl.gov/XCM/gmv/ GMV homepage]<br />
*[[Gnuplot]] -- [http://www.gnuplot.info/ gnuplot homepage]<br />
* GRI -- [http://gri.sourceforge.net/ GRI homepage]<br />
*[[Mayavi]] -- [http://mayavi.sourceforge.net/ MayaVi homepage]<br />
*[[OpenDX]] -- [http://www.opendx.org OpenDX homepage]<br />
*[[ParaView]] -- [http://www.paraview.org/HTML/Index.html ParaView homepage]<br />
*[[Tioga]] -- [http://www.kitp.ucsb.edu/~paxton/tioga.html Tioga homepage]<br />
*[[Vigie]] -- [http://www-sop.inria.fr/sinus/Softs/vigie.html Vigie homepage]<br />
*[[Visit]] -- [http://www.llnl.gov/visit Visit homepage]<br />
*[[vtk]] -- [http://www.vtk.org vtk homepage]<br />
*[[vtk.Net]] -- [http://vtkdotnet.sourceforge.net/ vtk.Net homepage]<br />
<br />
=== Miscellaneous ===<br />
<br />
*[[Engauge Digitizer]] -- [http://digitizer.sourceforge.net Engauge Digitizer homepage]<br />
*[[Ftnchek]] -- [http://www.dsm.fordham.edu/~ftnchek/ ftnchek homepage]<br />
*[[g3data]] -- [http://www.frantz.fi/software/g3data.php g3data homepage]<br />
* GIFMerge -- [http://www.the-labs.com/GIFMerge/ GIFMerge homepage]<br />
*[[Gifsicle]] -- [http://www.lcdf.org/~eddietwo/gifsicle/ Gifsicle homepage]<br />
*[[ImageMagick]] -- [http://www.imagemagick.org ImageMagick homepage]<br />
<br />
== Commercial codes ==<br />
<br />
=== Solvers ===<br />
<br />
*[[AcuSolve]] -- [http://www.acusim.com/ ACUSIM Software's homepage]<br />
*[[ADINA-F]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[ADINA-FSI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[ANSWER]] -- [http://www.acricfd.com/ ACRi's homepage]<br />
*[http://www.cfd-online.com/W/index.php?title=CFD%2B%2B CFD++] -- [http://www.metacomptech.com Metacomp Techonlogies' homepage]<br />
*[[CFD2000]] -- [http://www.adaptive-research.com/ Adaptive Research's homepage]<br />
*[[CFD-FASTRAN]] -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
*[[CFD-ACE]] -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
*[[CFdesign]] -- [http://www.cfdesign.com CFdesign's homepage]<br />
*[[CFX]] -- [http://www.ansys.com/ Ansys' homepage]<br />
*[[EFD - Engineering Fluid Dynamics]] -- [http://www.nika.biz/ Flomerics/NIKA homepage]<br />
*[[FENSAP-ICE]] -- [http://www.newmerical.com/ NTI' homepage]<br />
*[[FINE]] -- [http://www.numeca.be/ Numeca's homepage]<br />
*[[FIRE]] -- [http://www.avl.com/ AVL's homepage]<br />
*[[FLACS]] -- [http://www.gexcon.com/index.php?src=flacs/overview.html GexCon's homepage]<br />
*[[FLOW-3D]] -- [http://www.flow3d.com/ Flow Science's homepage]<br />
*[[FLOMERICS]]-- {http://www.flomerics.com Flomerics' homepage]<br />
*[[FLOWVISION]] -- [http://www.fv-tech.com FlowVision's homepage]<br />
*[[FLUENT]] -- [http://www.fluent.com Fluent's homepage]<br />
*[[FluSol]] -- [http://www.cfd-rocket.com FluSol's hompage]*[[J-FLO]] -- [http://www.newmerical.com NTI's homepage]<br />
*[[Flowz]]--[http://www.zeusnumerix.com Zeus Numerix's homepage ]<br />
*[[KINetics Reactive Flows]] -- [http://www.ReactionDesign.com Reaction Design's homepage]<br />
*[[KIVA]]--[http://www.lanl.gov/orgs/t/t3/codes/kiva.shtml Los Alamos homepage]<br />
*[[NOGRID FPM]] -- [http://www.no-grid.com NOGRIDS's homepage]<br />
*[[PHOENICS]] -- [http://www.cham.co.uk CHAM's homepage]<br />
*[[SPLASH]] -- [http://www.panix.com/~brosen SPLASH's homepage]<br />
*[[STAR-CD]] -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
*[[STAR-CCMplus]] -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
*[[Turb'Flow]] -- [http://www.fluorem.com Fluorem's hompage]<br />
<br />
=== Grid generation ===<br />
<br />
*[[ADINA-AUI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-GEOM]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFD-VISCART]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFDExpert-GridZ ]] --[http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
*[[Gridgen]] -- [http://www.pointwise.com/ Pointwise's homepage]<br />
*[[GridPro]] -- [http://www.gridpro.com/ PDC's homepage]<br />
*[[Harpoon]] -- [http://www.ensight.com/ CEI's homepage]<br />
*[[ICEM CFD ]] -- [http://www.ansys.com/ ANSYS' homepage]<br />
<br />
=== Visualization ===<br />
<br />
*[[ADINA-AUI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-VIEW]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFX-Post]] -- [http://www.ansys.com/ ANSYS' homepage]<br />
*[[COVISE]] -- [http://www.visenso.de/ Visenso's homepage]<br />
*[[EnSight]] -- [http://www.ensight.com/ CEI's homepage]<br />
*[[Fieldview]] -- [http://www.ilight.com/ Intelligent Light's homepage]<br />
*[[Tecplot]] -- [http://www.tecplot.com/ Tecplot's homepage]<br />
*[[ViewZ]] -- [http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
<br />
=== Systems ===<br />
<br />
*[[ADINA]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[Flownex]] -- [http://www.flownex.com/ Flownex's homepage]<br />
<br />
== Online tools and services ==<br />
<br />
*[[CFDNet]] -- [http://www.cfdnet.com/ CFDNet homepage]</div>Jasondhttp://www.cfd-online.com/Wiki/G3dataG3data2007-06-07T20:41:51Z<p>Jasond: Removed text that had been copied from the website</p>
<hr />
<div>g3data is an open source digitizing proram available under the terms of the GNU GPL. It is written in C.<br />
<br />
==External Link==<br />
* [http://www.frantz.fi/software/g3data.php g3data homepage]</div>Jasondhttp://www.cfd-online.com/Wiki/Engauge_DigitizerEngauge Digitizer2007-06-07T20:37:37Z<p>Jasond: Removed text that had been copied from the website</p>
<hr />
<div>Engauge Digitizer is an open source digitizing proram available under the terms of the GNU GPL. It is written in C++, and offers a number of features outline on the [http://digitizer.sourceforge.net webpage].<br />
<br />
==External Link==<br />
<br />
*[http://digitizer.sourceforge.net Engauge Digitizer]</div>Jasondhttp://www.cfd-online.com/Wiki/GnuplotGnuplot2007-06-07T20:31:03Z<p>Jasond: Removed text that had been copied from the website</p>
<hr />
<div>Gnuplot is a freely available interactive plotting utility. It is capable of producing 2D and 3D plots and supports a number of different output formats, including:<br />
*PostScript<br />
*PNG<br />
*SVG<br />
*LaTeX<br />
Gnuplot's primary interface is the command-line (though there are interfaces with other programs available), and it is one of the older free software programs still in development.<br />
<br />
==External Links==<br />
<br />
*[http://www.gnuplot.info/ Gnuplot homepage]<br />
*[http://www.gnuplot.info/docs/WhatsNew.html New features in version 4.2]</div>Jasondhttp://www.cfd-online.com/Wiki/DISLINDISLIN2007-06-07T20:17:06Z<p>Jasond: Reworked text that had been copied from the website</p>
<hr />
<div>DISLIN is a software library (with a number of available interfaces, including C, Fortran, Python, and Java) for visualization. DISLIN is free for non-commercial use and licenses are available for commercial use. <br />
<br />
== External Link ==<br />
*[http://www.dislin.de DISLIN homepage]</div>Jasondhttp://www.cfd-online.com/Wiki/OpenFlowerOpenFlower2007-06-07T20:06:22Z<p>Jasond: </p>
<hr />
<div>'''OpenFlower''' (literaly ''Open Source Flow Solver'') is a free open-source finite volume Computational Fluid Dynamics software, mainly devoted to the resolution of the turbulent incompressible Navier-Stokes equations, with scalar transport. It can deal with arbitrary complex geometries with hybrid meshes (supporting tetrahedrals, prisms, pyramids and hexahedrals), and is mainly devoted to the [[Large eddy simulation (LES)| large eddy simulation]] of turbulent flows. OpenFlower is interfaced with [[Gmsh]] (pre- post-processing) and [[Tecplot]] (post-processing).<br />
<br />
OpenFlower development was first launched on february 2004 by some CFD research engineers, willing to encourage common effort in research and developments in the area of Computational Fluid Dynamics. The main reason for this was (among other things) to federate the work of a multitude of PhD students and scientists who develop their own specific and effective codes, but which one day or the other will vanish as they change area of interest, or become unusable as time passes by... Moreover, the general trend shows that only some (expensive) commercial codes are<br />
available to treat complex geometries, whereas scientists in research labs can only mainly rely on these to accomplish research contracts with industry, when their home applications can only solve specific academic applications.<br />
<br />
The objective of an open-source CFD software such as OpenFlower becomes clear then :<br />
provide in a ”give & ask” basis a reliable CFD platform to develop models, numerical techniques and be available to respond to the increase of industrial needs in the field of CFD.<br />
OpenFlower development will mainly rely on:<br />
* the maintainment and developments integration of contributions coming from private institutes, research labs, PhD students... by the project administrators, who also provide the main development guidelines and starting basis;<br />
* the feedback of OpenFlower users, such as bug reports, patches, code development and optimisations.<br />
<br />
The scientific exchange of thousands of researchers and students of numerous fields of interest and skills can only be benefic in such an open-source code development environment, which surely will become an interesting way around closed commercial CFD codes.<br />
<br />
The main strength of OpenFlower is not only its open-source community working and<br />
hacking on it, but also a reliable colloborative framework and a well documented source of information for the fast development in the code and understanding its basic concepts and implemented physical modelings.<br />
<br />
==External links==<br />
<br />
*[http://openflower.sourceforge.net/ OpenFlower homepage]<br />
*[http://sourceforge.net/projects/openflower/ OpenFlower at SourceForge]</div>Jasondhttp://www.cfd-online.com/Wiki/Gerris_Flow_SolverGerris Flow Solver2007-06-07T20:03:52Z<p>Jasond: Reworked text that had been copied from the website</p>
<hr />
<div>Gerris is an open source finite volume code for the solution of the partial differential equations describing fluid flow. <br />
The source code, which is written in C, is licensed under the Free Software Foundation's GPL. Further information, including features, documentation, and sample cases are available [http://gfs.sourceforge.net/ here].<br />
<br />
==External Links==<br />
[http://gfs.sourceforge.net/ The Gerris Flow Solver Homepage]</div>Jasondhttp://www.cfd-online.com/Wiki/TochnogTochnog2007-06-07T19:57:53Z<p>Jasond: /* Tochnog */</p>
<hr />
<div>Tochnog is a GPLed CFD/ Multiphysics solver that seems to be less active since 2001. However, some people state that they used the code sucessfully for "stress analysis, diffusion and CFD".<br />
<br />
The official [http://tochnog.sourceforge.net homepage] is hosted by [http://sourceforge.net sourceforge.net].<br />
<br />
The capabilities at listed [http://tochnog.sourceforge.net/tnu/node9.html here], some exemplaric features are:<br />
*Implicit or explicit timesteping, Automatic time-stepping <br />
*Finite elements/Mesh refinement<br />
*Convection-diffusion equation, Navier Stokes, Solids deformations (e.g. Elasticity, Hypo-Plasticity, Damage, Thermal Stress, ...)<br />
*Error estimates<br />
*Automatic fluid-solid interaction<br />
*Static, quasi-static and dynamic analysis<br />
*Parallelization (e.g PETSc)<br />
*Inverse modeling (estimation of model parameters)</div>Jasondhttp://www.cfd-online.com/Wiki/Talk:CodesTalk:Codes2007-06-07T19:55:50Z<p>Jasond: </p>
<hr />
<div>I added a short note at the top of this page about limiting the length of the code descriptions - this is the result of a discussion in the wiki forum late last year - and I added a link to the copyright page to hopefully head off any more submissions of copyrighted material. I haven't started to look to hard at the individual pages yet - I'll start that later this week. Finally, I have removed all of the links to nonexistent pages in the free solvers section. I'm not sure how that looks. Any opinions? --[[User:Jasond|Jasond]] 15:48, 6 June 2007 (MDT)<br />
<br />
:It looks great I think. It is very good that someone works on the code section. It is one of the most frequented sections. About the description of the codes. What I think is most important is that we never accept any advertisements in these descriptions. Everything should be verifiable and objective truths. Hence, just writing that a code is accurate and uses state-of-the-art models and numerics is not good. Describing which models and methods that are used should be okay though, as long as adjectives like "good", "accurate", "best" etc. are used very sparingly. About the copyright issue. We must of course ensure that we don't break any copyrights. However, I don't think that companies will have any problems with using their descriptions of their codes, on the opposite, that is probably what they want. Some descriptions have also been written by the code companies themselves. For example, the [[Gridgen]] description was written by John Chawner and Rick Matus, two of the top people in Pointwise. It is really not that good that companies themselves write these decriptions since that has a tendency to always produce advertising material. Pointwise have been very good at avoiding advertisements and unverifiable adjectives though. --[[User:Jola|Jola]] 03:22, 7 June 2007 (MDT)<br />
<br />
::I guess that I generally agree. However, the webpage copying looks to be more widespread than I initially thought. I would rather have no description pages at all than have pages that are cut-and-paste jobs. On the [[Gridgen]] page, I guess my objection is that it is rather long - and they have their own web presence for that sort of thing. It does fit your requirements, though, and maybe we should add the part about "verifiable and objective truths" to the text on the code page. --[[User:Jasond|Jasond]] 13:55, 7 June 2007 (MDT)</div>Jasondhttp://www.cfd-online.com/Wiki/FtnchekFtnchek2007-06-07T19:06:35Z<p>Jasond: Reworked text that had been copied from the website</p>
<hr />
<div>ftnchek is a static analyzer for Fortran 77 programs. It intended to detect defects in Fortran code that are legal but may cause problems. As such, it is not a debugger, but will find issues like<br />
* unused variables<br />
* uninitialized variables<br />
The program will not catch all syntax errors, so it should be used in conjunction with a compiler.<br />
<br />
==External Link==<br />
*[http://www.dsm.fordham.edu/~ftnchek/ Ftnchek homepage]</div>Jasondhttp://www.cfd-online.com/Wiki/ImageMagickImageMagick2007-06-07T18:58:20Z<p>Jasond: New page: ImageMagick is a free software suite for the manipulation of images. It is usually used from the command line, but a number of other interfaces are available, including as a software libra...</p>
<hr />
<div>ImageMagick is a free software suite for the manipulation of images. It is usually used from the command line, but a number of other interfaces are available, including as a software library. ImageMagick can be very helpful in the preparation of animations, particlulary if you have many images that require the same modification. It is particularly useful when building movies from Fluent.<br />
<br />
== External Links==<br />
*[http://www.imagemagick.org ImageMagick homepage]<br />
*[http://www.imagemagick.org/Usage/ ImageMagick examples]</div>Jasondhttp://www.cfd-online.com/Wiki/CodesCodes2007-06-07T18:52:13Z<p>Jasond: /* Miscellaneous */</p>
<hr />
<div>An overview of both free and commercial CFD software. Here you will find short descriptions of codes along with links to resources.<br />
<br />
Note to contributers: Please try to keep descriptions short and to the point (approximately 200 words) and avoid long lists of features or capabilities. Also keep in mind that all contributions are considered to be released under the GNU Free Documentation License 1.2 (see [[Project:Copyrights]] for details). <br />
<br />
== Free codes ==<br />
<br />
This section lists codes that are in the public domain, and codes that are available under GPL, BSD or similar licenses.<br />
<br />
=== Solvers ===<br />
<br />
* ADFC -- [http://adfc.sourceforge.net/index.html ADFC homepage]<br />
* Diagonalized Upwind Navier Stokes -- [http://duns.sourceforge.net DUNS homepage]<br />
* Dolfyn -- [http://www.dolfyn.net/dolfyn/index_en.html dolfyn homepage]<br />
*[[Edge]] -- [http://www.edge.foi.se/ Edge homepage]<br />
*[[ELMER]] -- [http://www.csc.fi/elmer/ ELMER homepage]<br />
* Featflow -- [http://www.featflow.de Featflow homepage]<br />
* Femwater -- [http://www.cee.odu.edu/model/femwater.php Femwater code]<br />
* FreeFEM -- [http://www.freefem.org FreeFEM homepage]<br />
*[[Gerris Flow Solver]] -- [http://gfs.sourceforge.net/ Gerris Flow Solver homepage]<br />
* IMTEK Mathematica Supplement (IMS) -- [http://www.imtek.uni-freiburg.de/simulation/mathematica/IMSweb/ IMTEK Mathematica Supplement (IMS) homepage]<br />
* iNavier -- [http://inavier.sourceforge.net/ iNavier Solver Home Page]<br />
* MFIX -- [http://www.mfix.org Computational multiphase flow homepage]<br />
*[[NaSt2D-2.0]] -- [http://home.arcor.de/drklaus.bauerfeind/nast/eNaSt2D.html NaSt2D-2.0 homepage]<br />
*[[NSC2KE]] -- [http://www-rocq1.inria.fr/gamma/cdrom/www/nsc2ke/eng.htm NSC2KE homepage]<br />
*[[OpenFlower]] -- [http://sourceforge.net/projects/openflower/ OpenFlower homepage]<br />
*[[OpenFOAM]] -- [http://www.openfoam.org/ OpenFOAM homepage]<br />
* OpenFVM -- [http://openfvm.sourceforge.net/ OpenFVM homepage]<br />
* PETSc-FEM -- [http://www.cimec.org.ar/petscfem PETSc-FEM homepage]<br />
* PP3D -- [http://www.featflow.de/ parpp3d++ homepage]<br />
* SLFCFD -- [http://slfcfd.sourceforge.net SLFCFD homepage]<br />
*[[SSIIM]] -- [http://folk.ntnu.no/nilsol/cfd/ CFD at NTNU]<br />
*[[Tochnog]] -- [http://tochnog.sourceforge.net Tochnog homepage]<br />
* Typhon solver -- [http://typhon.sf.net Typhon solver homepage]<br />
<br />
=== Grid generation ===<br />
<br />
*[[Delaundo]] -- [http://www.cerfacs.fr/~muller/delaundo.html Delaundo homepage]<br />
* GMSH -- [http://www.geuz.org/gmsh/ GMSH hompage]<br />
* NETGEN -- [http://www.hpfem.jku.at/netgen/ NETGEN homepage]<br />
* SALOME -- [http://www.salome-platform.org SALOME homepage]<br />
* TETGEN -- [http://tetgen.berlios.de/ TETGEN hompage]<br />
*[[Triangle]] -- [http://www.cs.cmu.edu/~quake/triangle.html Triangle homepage]<br />
<br />
=== Visualization ===<br />
*[[DISLIN]] -- [http://www.mps.mpg.de/dislin/server.html DISLIN homepage]<br />
* GMV -- [http://www-xdiv.lanl.gov/XCM/gmv/ GMV homepage]<br />
*[[Gnuplot]] -- [http://www.gnuplot.info/ gnuplot homepage]<br />
* GRI -- [http://gri.sourceforge.net/ GRI homepage]<br />
*[[Mayavi]] -- [http://mayavi.sourceforge.net/ MayaVi homepage]<br />
*[[OpenDX]] -- [http://www.opendx.org OpenDX homepage]<br />
*[[ParaView]] -- [http://www.paraview.org/HTML/Index.html ParaView homepage]<br />
*[[Tioga]] -- [http://www.kitp.ucsb.edu/~paxton/tioga.html Tioga homepage]<br />
*[[Vigie]] -- [http://www-sop.inria.fr/sinus/Softs/vigie.html Vigie homepage]<br />
*[[Visit]] -- [http://www.llnl.gov/visit Visit homepage]<br />
*[[vtk]] -- [http://www.vtk.org vtk homepage]<br />
*[[vtk.Net]] -- [http://vtkdotnet.sourceforge.net/ vtk.Net homepage]<br />
<br />
=== Miscellaneous ===<br />
<br />
*[[Engauge Digitizer]] -- [http://digitizer.sourceforge.net Engauge Digitizer homepage]<br />
*[[Ftnchek]] -- [http://www.dsm.fordham.edu/~ftnchek/ ftnchek homepage]<br />
*[[g3data]] -- [http://www.frantz.fi/index.php?page=software g3data homepage]<br />
* GIFMerge -- [http://www.the-labs.com/GIFMerge/ GIFMerge homepage]<br />
*[[Gifsicle]] -- [http://www.lcdf.org/~eddietwo/gifsicle/ Gifsicle homepage]<br />
*[[ImageMagick]] -- [http://www.imagemagick.org ImageMagick homepage]<br />
<br />
== Commercial codes ==<br />
<br />
=== Solvers ===<br />
<br />
*[[AcuSolve]] -- [http://www.acusim.com/ ACUSIM Software's homepage]<br />
*[[ADINA-F]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[ADINA-FSI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[ANSWER]] -- [http://www.acricfd.com/ ACRi's homepage]<br />
*[http://www.cfd-online.com/W/index.php?title=CFD%2B%2B CFD++] -- [http://www.metacomptech.com Metacomp Techonlogies' homepage]<br />
*[[CFD2000]] -- [http://www.adaptive-research.com/ Adaptive Research's homepage]<br />
*[[CFD-FASTRAN]] -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
*[[CFD-ACE]] -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
*[[CFdesign]] -- [http://www.cfdesign.com CFdesign's homepage]<br />
*[[CFX]] -- [http://www.ansys.com/ Ansys' homepage]<br />
*[[EFD - Engineering Fluid Dynamics]] -- [http://www.nika.biz/ Flomerics/NIKA homepage]<br />
*[[FENSAP-ICE]] -- [http://www.newmerical.com/ NTI' homepage]<br />
*[[FINE]] -- [http://www.numeca.be/ Numeca's homepage]<br />
*[[FIRE]] -- [http://www.avl.com/ AVL's homepage]<br />
*[[FLACS]] -- [http://www.gexcon.com/index.php?src=flacs/overview.html GexCon's homepage]<br />
*[[FLOW-3D]] -- [http://www.flow3d.com/ Flow Science's homepage]<br />
*[[FLOMERICS]]-- {http://www.flomerics.com Flomerics' homepage]<br />
*[[FLOWVISION]] -- [http://www.fv-tech.com FlowVision's homepage]<br />
*[[FLUENT]] -- [http://www.fluent.com Fluent's homepage]<br />
*[[FluSol]] -- [http://www.cfd-rocket.com FluSol's hompage]*[[J-FLO]] -- [http://www.newmerical.com NTI's homepage]<br />
*[[Flowz]]--[http://www.zeusnumerix.com Zeus Numerix's homepage ]<br />
*[[KINetics Reactive Flows]] -- [http://www.ReactionDesign.com Reaction Design's homepage]<br />
*[[KIVA]]--[http://www.lanl.gov/orgs/t/t3/codes/kiva.shtml Los Alamos homepage]<br />
*[[NOGRID FPM]] -- [http://www.no-grid.com NOGRIDS's homepage]<br />
*[[PHOENICS]] -- [http://www.cham.co.uk CHAM's homepage]<br />
*[[SPLASH]] -- [http://www.panix.com/~brosen SPLASH's homepage]<br />
*[[STAR-CD]] -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
*[[STAR-CCMplus]] -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
*[[Turb'Flow]] -- [http://www.fluorem.com Fluorem's hompage]<br />
<br />
=== Grid generation ===<br />
<br />
*[[ADINA-AUI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-GEOM]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFD-VISCART]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFDExpert-GridZ ]] --[http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
*[[Gridgen]] -- [http://www.pointwise.com/ Pointwise's homepage]<br />
*[[GridPro]] -- [http://www.gridpro.com/ PDC's homepage]<br />
*[[Harpoon]] -- [http://www.ensight.com/ CEI's homepage]<br />
*[[ICEM CFD ]] -- [http://www.ansys.com/ ANSYS' homepage]<br />
<br />
=== Visualization ===<br />
<br />
*[[ADINA-AUI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-VIEW]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFX-Post]] -- [http://www.ansys.com/ ANSYS' homepage]<br />
*[[COVISE]] -- [http://www.visenso.de/ Visenso's homepage]<br />
*[[EnSight]] -- [http://www.ensight.com/ CEI's homepage]<br />
*[[Fieldview]] -- [http://www.ilight.com/ Intelligent Light's homepage]<br />
*[[Tecplot]] -- [http://www.tecplot.com/ Tecplot's homepage]<br />
*[[ViewZ]] -- [http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
<br />
=== Systems ===<br />
<br />
*[[ADINA]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[Flownex]] -- [http://www.flownex.com/ Flownex's homepage]<br />
<br />
== Online tools and services ==<br />
<br />
*[[CFDNet]] -- [http://www.cfdnet.com/ CFDNet homepage]</div>Jasondhttp://www.cfd-online.com/Wiki/TiogaTioga2007-06-07T18:40:18Z<p>Jasond: </p>
<hr />
<div>Tioga is a Ruby library for scientific plotting which uses pdfTeX as a renderer. This allows production of publication quality vector format graphics. Almost any (La)TeX text/formulas may appear in the image and are rendered properly.<br />
<br />
Example of Tioga visualization:<br />
<br />
[[Image:tioga_opacity_eos.jpg]]<br />
<br />
Tioga is limited to 2D visualization. It is particulary useful for traditional function plots, 2D fields in false color, and contour plotting.<br />
<br />
Tioga is Free Software.<br />
<br />
== External Link ==<br />
*[http://www.kitp.ucsb.edu/~paxton/tioga.html Tioga plotting software homepage]</div>Jasondhttp://www.cfd-online.com/Wiki/GnuplotGnuplot2007-06-07T18:38:57Z<p>Jasond: /* External Links */</p>
<hr />
<div>Gnuplot is a portable command-line driven interactive data and function plotting utility for UNIX, IBM OS/2, MS Windows, DOS, Macintosh, VMS, Atari and many other platforms. The software is copyrighted but freely distributed (i.e., you don't have to pay for it). It was originally intended as to allow scientists and students to visualize mathematical functions and data. It does this job pretty well, but has grown to support many non-interactive uses, including web scripting and integration as a plotting engine for third-party applications like Octave. Gnuplot has been supported and under development since 1986.<br />
<br />
Gnuplot supports many types of plots in either 2D and 3D. It can draw using lines, points, boxes, contours, vector fields, surfaces, and various associated text. It also supports various specialized plot types.<br />
<br />
Gnuplot supports many different types of terminals: interactive screen terminals (with mouse and hotkey functionality), pen plotters (like hpgl), printers (including postscript and many color devices), and printings to output file as vectorial pseudo-devices like LaTeX, metafont, pdf, svg, or bitmap png. Gnuplot is easily extensible to include new devices. <br />
<br />
<br />
==External Links==<br />
<br />
*[http://www.gnuplot.info/ Gnuplot homepage]<br />
*[http://www.gnuplot.info/docs/WhatsNew.html New features in version 4.2]</div>Jasondhttp://www.cfd-online.com/Wiki/GnuplotGnuplot2007-06-07T18:37:34Z<p>Jasond: </p>
<hr />
<div>Gnuplot is a portable command-line driven interactive data and function plotting utility for UNIX, IBM OS/2, MS Windows, DOS, Macintosh, VMS, Atari and many other platforms. The software is copyrighted but freely distributed (i.e., you don't have to pay for it). It was originally intended as to allow scientists and students to visualize mathematical functions and data. It does this job pretty well, but has grown to support many non-interactive uses, including web scripting and integration as a plotting engine for third-party applications like Octave. Gnuplot has been supported and under development since 1986.<br />
<br />
Gnuplot supports many types of plots in either 2D and 3D. It can draw using lines, points, boxes, contours, vector fields, surfaces, and various associated text. It also supports various specialized plot types.<br />
<br />
Gnuplot supports many different types of terminals: interactive screen terminals (with mouse and hotkey functionality), pen plotters (like hpgl), printers (including postscript and many color devices), and printings to output file as vectorial pseudo-devices like LaTeX, metafont, pdf, svg, or bitmap png. Gnuplot is easily extensible to include new devices. <br />
<br />
<br />
==External Links==<br />
<br />
*[http://www.gnuplot.info/ Gnuplot homepage]<br />
*[http://www.gnuplot.info/docs/gnuplot.html#What_is_New_in_Version_4.0 New features in version 4.0]</div>Jasondhttp://www.cfd-online.com/Wiki/CodesCodes2007-06-07T18:36:55Z<p>Jasond: /* Visualization */</p>
<hr />
<div>An overview of both free and commercial CFD software. Here you will find short descriptions of codes along with links to resources.<br />
<br />
Note to contributers: Please try to keep descriptions short and to the point (approximately 200 words) and avoid long lists of features or capabilities. Also keep in mind that all contributions are considered to be released under the GNU Free Documentation License 1.2 (see [[Project:Copyrights]] for details). <br />
<br />
== Free codes ==<br />
<br />
This section lists codes that are in the public domain, and codes that are available under GPL, BSD or similar licenses.<br />
<br />
=== Solvers ===<br />
<br />
* ADFC -- [http://adfc.sourceforge.net/index.html ADFC homepage]<br />
* Diagonalized Upwind Navier Stokes -- [http://duns.sourceforge.net DUNS homepage]<br />
* Dolfyn -- [http://www.dolfyn.net/dolfyn/index_en.html dolfyn homepage]<br />
*[[Edge]] -- [http://www.edge.foi.se/ Edge homepage]<br />
*[[ELMER]] -- [http://www.csc.fi/elmer/ ELMER homepage]<br />
* Featflow -- [http://www.featflow.de Featflow homepage]<br />
* Femwater -- [http://www.cee.odu.edu/model/femwater.php Femwater code]<br />
* FreeFEM -- [http://www.freefem.org FreeFEM homepage]<br />
*[[Gerris Flow Solver]] -- [http://gfs.sourceforge.net/ Gerris Flow Solver homepage]<br />
* IMTEK Mathematica Supplement (IMS) -- [http://www.imtek.uni-freiburg.de/simulation/mathematica/IMSweb/ IMTEK Mathematica Supplement (IMS) homepage]<br />
* iNavier -- [http://inavier.sourceforge.net/ iNavier Solver Home Page]<br />
* MFIX -- [http://www.mfix.org Computational multiphase flow homepage]<br />
*[[NaSt2D-2.0]] -- [http://home.arcor.de/drklaus.bauerfeind/nast/eNaSt2D.html NaSt2D-2.0 homepage]<br />
*[[NSC2KE]] -- [http://www-rocq1.inria.fr/gamma/cdrom/www/nsc2ke/eng.htm NSC2KE homepage]<br />
*[[OpenFlower]] -- [http://sourceforge.net/projects/openflower/ OpenFlower homepage]<br />
*[[OpenFOAM]] -- [http://www.openfoam.org/ OpenFOAM homepage]<br />
* OpenFVM -- [http://openfvm.sourceforge.net/ OpenFVM homepage]<br />
* PETSc-FEM -- [http://www.cimec.org.ar/petscfem PETSc-FEM homepage]<br />
* PP3D -- [http://www.featflow.de/ parpp3d++ homepage]<br />
* SLFCFD -- [http://slfcfd.sourceforge.net SLFCFD homepage]<br />
*[[SSIIM]] -- [http://folk.ntnu.no/nilsol/cfd/ CFD at NTNU]<br />
*[[Tochnog]] -- [http://tochnog.sourceforge.net Tochnog homepage]<br />
* Typhon solver -- [http://typhon.sf.net Typhon solver homepage]<br />
<br />
=== Grid generation ===<br />
<br />
*[[Delaundo]] -- [http://www.cerfacs.fr/~muller/delaundo.html Delaundo homepage]<br />
* GMSH -- [http://www.geuz.org/gmsh/ GMSH hompage]<br />
* NETGEN -- [http://www.hpfem.jku.at/netgen/ NETGEN homepage]<br />
* SALOME -- [http://www.salome-platform.org SALOME homepage]<br />
* TETGEN -- [http://tetgen.berlios.de/ TETGEN hompage]<br />
*[[Triangle]] -- [http://www.cs.cmu.edu/~quake/triangle.html Triangle homepage]<br />
<br />
=== Visualization ===<br />
*[[DISLIN]] -- [http://www.mps.mpg.de/dislin/server.html DISLIN homepage]<br />
* GMV -- [http://www-xdiv.lanl.gov/XCM/gmv/ GMV homepage]<br />
*[[Gnuplot]] -- [http://www.gnuplot.info/ gnuplot homepage]<br />
* GRI -- [http://gri.sourceforge.net/ GRI homepage]<br />
*[[Mayavi]] -- [http://mayavi.sourceforge.net/ MayaVi homepage]<br />
*[[OpenDX]] -- [http://www.opendx.org OpenDX homepage]<br />
*[[ParaView]] -- [http://www.paraview.org/HTML/Index.html ParaView homepage]<br />
*[[Tioga]] -- [http://www.kitp.ucsb.edu/~paxton/tioga.html Tioga homepage]<br />
*[[Vigie]] -- [http://www-sop.inria.fr/sinus/Softs/vigie.html Vigie homepage]<br />
*[[Visit]] -- [http://www.llnl.gov/visit Visit homepage]<br />
*[[vtk]] -- [http://www.vtk.org vtk homepage]<br />
*[[vtk.Net]] -- [http://vtkdotnet.sourceforge.net/ vtk.Net homepage]<br />
<br />
=== Miscellaneous ===<br />
<br />
*[[Engauge Digitizer]]<br />
*[[Ftnchek]]<br />
*[[g3data]] -- [http://www.frantz.fi/index.php?page=software g3data homepage]<br />
*[[GIFMerge]] -- [http://www.the-labs.com/GIFMerge/ GIFMerge homepage]<br />
*[[Gifsicle]]<br />
<br />
== Commercial codes ==<br />
<br />
=== Solvers ===<br />
<br />
*[[AcuSolve]] -- [http://www.acusim.com/ ACUSIM Software's homepage]<br />
*[[ADINA-F]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[ADINA-FSI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[ANSWER]] -- [http://www.acricfd.com/ ACRi's homepage]<br />
*[http://www.cfd-online.com/W/index.php?title=CFD%2B%2B CFD++] -- [http://www.metacomptech.com Metacomp Techonlogies' homepage]<br />
*[[CFD2000]] -- [http://www.adaptive-research.com/ Adaptive Research's homepage]<br />
*[[CFD-FASTRAN]] -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
*[[CFD-ACE]] -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
*[[CFdesign]] -- [http://www.cfdesign.com CFdesign's homepage]<br />
*[[CFX]] -- [http://www.ansys.com/ Ansys' homepage]<br />
*[[EFD - Engineering Fluid Dynamics]] -- [http://www.nika.biz/ Flomerics/NIKA homepage]<br />
*[[FENSAP-ICE]] -- [http://www.newmerical.com/ NTI' homepage]<br />
*[[FINE]] -- [http://www.numeca.be/ Numeca's homepage]<br />
*[[FIRE]] -- [http://www.avl.com/ AVL's homepage]<br />
*[[FLACS]] -- [http://www.gexcon.com/index.php?src=flacs/overview.html GexCon's homepage]<br />
*[[FLOW-3D]] -- [http://www.flow3d.com/ Flow Science's homepage]<br />
*[[FLOMERICS]]-- {http://www.flomerics.com Flomerics' homepage]<br />
*[[FLOWVISION]] -- [http://www.fv-tech.com FlowVision's homepage]<br />
*[[FLUENT]] -- [http://www.fluent.com Fluent's homepage]<br />
*[[FluSol]] -- [http://www.cfd-rocket.com FluSol's hompage]*[[J-FLO]] -- [http://www.newmerical.com NTI's homepage]<br />
*[[Flowz]]--[http://www.zeusnumerix.com Zeus Numerix's homepage ]<br />
*[[KINetics Reactive Flows]] -- [http://www.ReactionDesign.com Reaction Design's homepage]<br />
*[[KIVA]]--[http://www.lanl.gov/orgs/t/t3/codes/kiva.shtml Los Alamos homepage]<br />
*[[NOGRID FPM]] -- [http://www.no-grid.com NOGRIDS's homepage]<br />
*[[PHOENICS]] -- [http://www.cham.co.uk CHAM's homepage]<br />
*[[SPLASH]] -- [http://www.panix.com/~brosen SPLASH's homepage]<br />
*[[STAR-CD]] -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
*[[STAR-CCMplus]] -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
*[[Turb'Flow]] -- [http://www.fluorem.com Fluorem's hompage]<br />
<br />
=== Grid generation ===<br />
<br />
*[[ADINA-AUI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-GEOM]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFD-VISCART]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFDExpert-GridZ ]] --[http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
*[[Gridgen]] -- [http://www.pointwise.com/ Pointwise's homepage]<br />
*[[GridPro]] -- [http://www.gridpro.com/ PDC's homepage]<br />
*[[Harpoon]] -- [http://www.ensight.com/ CEI's homepage]<br />
*[[ICEM CFD ]] -- [http://www.ansys.com/ ANSYS' homepage]<br />
<br />
=== Visualization ===<br />
<br />
*[[ADINA-AUI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-VIEW]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFX-Post]] -- [http://www.ansys.com/ ANSYS' homepage]<br />
*[[COVISE]] -- [http://www.visenso.de/ Visenso's homepage]<br />
*[[EnSight]] -- [http://www.ensight.com/ CEI's homepage]<br />
*[[Fieldview]] -- [http://www.ilight.com/ Intelligent Light's homepage]<br />
*[[Tecplot]] -- [http://www.tecplot.com/ Tecplot's homepage]<br />
*[[ViewZ]] -- [http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
<br />
=== Systems ===<br />
<br />
*[[ADINA]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[Flownex]] -- [http://www.flownex.com/ Flownex's homepage]<br />
<br />
== Online tools and services ==<br />
<br />
*[[CFDNet]] -- [http://www.cfdnet.com/ CFDNet homepage]</div>Jasondhttp://www.cfd-online.com/Wiki/OpenDXOpenDX2007-06-07T18:36:39Z<p>Jasond: </p>
<hr />
<div>OpenDx is visualization package developed by IBM. It is the open source version of IBM's Data Explorer. The latest version is 3.1.4B .<br />
<br />
==External Link==<br />
*[http://www.opendx.org OpenDX homepage]</div>Jasondhttp://www.cfd-online.com/Wiki/VisitVisit2007-06-07T18:01:27Z<p>Jasond: Removed text that had been copied from the VisIt website</p>
<hr />
<div>VisIt is an open source (available under the BSD license) visualization system developed by the Department of Energy (DOE) Advanced Simulation and Computing Initiative (ASCI) for the visualization of large data sets. A summary of key features is available [http://www.llnl.gov/visit/about.html here]. VisIt runs on a variety of platforms, including Linux, MacOSX, and Windows (precompiled executables are available). VisIt is an interactive system system, but can also be extended and customized using C++, Java, or Python. The system has been under development since summer 2000 and is under active development as of April 2007 (release of version 1.6)<br />
<br />
==External Links==<br />
*[http://www.llnl.gov/visit VisIt homepage]<br />
*[http://www.llnl.gov/visit/about.html VisIt Features].</div>Jasondhttp://www.cfd-online.com/Wiki/CodesCodes2007-06-07T17:36:01Z<p>Jasond: /* Visualization */</p>
<hr />
<div>An overview of both free and commercial CFD software. Here you will find short descriptions of codes along with links to resources.<br />
<br />
Note to contributers: Please try to keep descriptions short and to the point (approximately 200 words) and avoid long lists of features or capabilities. Also keep in mind that all contributions are considered to be released under the GNU Free Documentation License 1.2 (see [[Project:Copyrights]] for details). <br />
<br />
== Free codes ==<br />
<br />
This section lists codes that are in the public domain, and codes that are available under GPL, BSD or similar licenses.<br />
<br />
=== Solvers ===<br />
<br />
* ADFC -- [http://adfc.sourceforge.net/index.html ADFC homepage]<br />
* Diagonalized Upwind Navier Stokes -- [http://duns.sourceforge.net DUNS homepage]<br />
* Dolfyn -- [http://www.dolfyn.net/dolfyn/index_en.html dolfyn homepage]<br />
*[[Edge]] -- [http://www.edge.foi.se/ Edge homepage]<br />
*[[ELMER]] -- [http://www.csc.fi/elmer/ ELMER homepage]<br />
* Featflow -- [http://www.featflow.de Featflow homepage]<br />
* Femwater -- [http://www.cee.odu.edu/model/femwater.php Femwater code]<br />
* FreeFEM -- [http://www.freefem.org FreeFEM homepage]<br />
*[[Gerris Flow Solver]] -- [http://gfs.sourceforge.net/ Gerris Flow Solver homepage]<br />
* IMTEK Mathematica Supplement (IMS) -- [http://www.imtek.uni-freiburg.de/simulation/mathematica/IMSweb/ IMTEK Mathematica Supplement (IMS) homepage]<br />
* iNavier -- [http://inavier.sourceforge.net/ iNavier Solver Home Page]<br />
* MFIX -- [http://www.mfix.org Computational multiphase flow homepage]<br />
*[[NaSt2D-2.0]] -- [http://home.arcor.de/drklaus.bauerfeind/nast/eNaSt2D.html NaSt2D-2.0 homepage]<br />
*[[NSC2KE]] -- [http://www-rocq1.inria.fr/gamma/cdrom/www/nsc2ke/eng.htm NSC2KE homepage]<br />
*[[OpenFlower]] -- [http://sourceforge.net/projects/openflower/ OpenFlower homepage]<br />
*[[OpenFOAM]] -- [http://www.openfoam.org/ OpenFOAM homepage]<br />
* OpenFVM -- [http://openfvm.sourceforge.net/ OpenFVM homepage]<br />
* PETSc-FEM -- [http://www.cimec.org.ar/petscfem PETSc-FEM homepage]<br />
* PP3D -- [http://www.featflow.de/ parpp3d++ homepage]<br />
* SLFCFD -- [http://slfcfd.sourceforge.net SLFCFD homepage]<br />
*[[SSIIM]] -- [http://folk.ntnu.no/nilsol/cfd/ CFD at NTNU]<br />
*[[Tochnog]] -- [http://tochnog.sourceforge.net Tochnog homepage]<br />
* Typhon solver -- [http://typhon.sf.net Typhon solver homepage]<br />
<br />
=== Grid generation ===<br />
<br />
*[[Delaundo]] -- [http://www.cerfacs.fr/~muller/delaundo.html Delaundo homepage]<br />
* GMSH -- [http://www.geuz.org/gmsh/ GMSH hompage]<br />
* NETGEN -- [http://www.hpfem.jku.at/netgen/ NETGEN homepage]<br />
* SALOME -- [http://www.salome-platform.org SALOME homepage]<br />
* TETGEN -- [http://tetgen.berlios.de/ TETGEN hompage]<br />
*[[Triangle]] -- [http://www.cs.cmu.edu/~quake/triangle.html Triangle homepage]<br />
<br />
=== Visualization ===<br />
*[[DISLIN]] -- [http://www.mps.mpg.de/dislin/server.html DISLIN homepage]<br />
* GMV -- [http://www-xdiv.lanl.gov/XCM/gmv/ GMV homepage]<br />
*[[Gnuplot]] -- [http://www.gnuplot.info/ gnuplot homepage]<br />
* GRI -- [http://gri.sourceforge.net/ GRI homepage]<br />
*[[Mayavi]] -- [http://mayavi.sourceforge.net/ MayaVi homepage]<br />
*[[OpenDX]] <br />
*[[ParaView]] -- [http://www.paraview.org/HTML/Index.html ParaView homepage]<br />
*[[Tioga]] -- [http://www.kitp.ucsb.edu/~paxton/tioga.html Tioga homepage]<br />
*[[Vigie]] -- [http://www-sop.inria.fr/sinus/Softs/vigie.html Vigie homepage]<br />
*[[Visit]] -- [http://www.llnl.gov/visit Visit homepage]<br />
*[[vtk]] -- [http://www.vtk.org vtk homepage]<br />
*[[vtk.Net]] -- [http://vtkdotnet.sourceforge.net/ vtk.Net homepage]<br />
<br />
=== Miscellaneous ===<br />
<br />
*[[Engauge Digitizer]]<br />
*[[Ftnchek]]<br />
*[[g3data]] -- [http://www.frantz.fi/index.php?page=software g3data homepage]<br />
*[[GIFMerge]] -- [http://www.the-labs.com/GIFMerge/ GIFMerge homepage]<br />
*[[Gifsicle]]<br />
<br />
== Commercial codes ==<br />
<br />
=== Solvers ===<br />
<br />
*[[AcuSolve]] -- [http://www.acusim.com/ ACUSIM Software's homepage]<br />
*[[ADINA-F]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[ADINA-FSI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[ANSWER]] -- [http://www.acricfd.com/ ACRi's homepage]<br />
*[http://www.cfd-online.com/W/index.php?title=CFD%2B%2B CFD++] -- [http://www.metacomptech.com Metacomp Techonlogies' homepage]<br />
*[[CFD2000]] -- [http://www.adaptive-research.com/ Adaptive Research's homepage]<br />
*[[CFD-FASTRAN]] -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
*[[CFD-ACE]] -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
*[[CFdesign]] -- [http://www.cfdesign.com CFdesign's homepage]<br />
*[[CFX]] -- [http://www.ansys.com/ Ansys' homepage]<br />
*[[EFD - Engineering Fluid Dynamics]] -- [http://www.nika.biz/ Flomerics/NIKA homepage]<br />
*[[FENSAP-ICE]] -- [http://www.newmerical.com/ NTI' homepage]<br />
*[[FINE]] -- [http://www.numeca.be/ Numeca's homepage]<br />
*[[FIRE]] -- [http://www.avl.com/ AVL's homepage]<br />
*[[FLACS]] -- [http://www.gexcon.com/index.php?src=flacs/overview.html GexCon's homepage]<br />
*[[FLOW-3D]] -- [http://www.flow3d.com/ Flow Science's homepage]<br />
*[[FLOMERICS]]-- {http://www.flomerics.com Flomerics' homepage]<br />
*[[FLOWVISION]] -- [http://www.fv-tech.com FlowVision's homepage]<br />
*[[FLUENT]] -- [http://www.fluent.com Fluent's homepage]<br />
*[[FluSol]] -- [http://www.cfd-rocket.com FluSol's hompage]*[[J-FLO]] -- [http://www.newmerical.com NTI's homepage]<br />
*[[Flowz]]--[http://www.zeusnumerix.com Zeus Numerix's homepage ]<br />
*[[KINetics Reactive Flows]] -- [http://www.ReactionDesign.com Reaction Design's homepage]<br />
*[[KIVA]]--[http://www.lanl.gov/orgs/t/t3/codes/kiva.shtml Los Alamos homepage]<br />
*[[NOGRID FPM]] -- [http://www.no-grid.com NOGRIDS's homepage]<br />
*[[PHOENICS]] -- [http://www.cham.co.uk CHAM's homepage]<br />
*[[SPLASH]] -- [http://www.panix.com/~brosen SPLASH's homepage]<br />
*[[STAR-CD]] -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
*[[STAR-CCMplus]] -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
*[[Turb'Flow]] -- [http://www.fluorem.com Fluorem's hompage]<br />
<br />
=== Grid generation ===<br />
<br />
*[[ADINA-AUI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-GEOM]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFD-VISCART]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFDExpert-GridZ ]] --[http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
*[[Gridgen]] -- [http://www.pointwise.com/ Pointwise's homepage]<br />
*[[GridPro]] -- [http://www.gridpro.com/ PDC's homepage]<br />
*[[Harpoon]] -- [http://www.ensight.com/ CEI's homepage]<br />
*[[ICEM CFD ]] -- [http://www.ansys.com/ ANSYS' homepage]<br />
<br />
=== Visualization ===<br />
<br />
*[[ADINA-AUI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-VIEW]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFX-Post]] -- [http://www.ansys.com/ ANSYS' homepage]<br />
*[[COVISE]] -- [http://www.visenso.de/ Visenso's homepage]<br />
*[[EnSight]] -- [http://www.ensight.com/ CEI's homepage]<br />
*[[Fieldview]] -- [http://www.ilight.com/ Intelligent Light's homepage]<br />
*[[Tecplot]] -- [http://www.tecplot.com/ Tecplot's homepage]<br />
*[[ViewZ]] -- [http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
<br />
=== Systems ===<br />
<br />
*[[ADINA]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[Flownex]] -- [http://www.flownex.com/ Flownex's homepage]<br />
<br />
== Online tools and services ==<br />
<br />
*[[CFDNet]] -- [http://www.cfdnet.com/ CFDNet homepage]</div>Jasondhttp://www.cfd-online.com/Wiki/CodesCodes2007-06-07T17:31:26Z<p>Jasond: /* Visualization */</p>
<hr />
<div>An overview of both free and commercial CFD software. Here you will find short descriptions of codes along with links to resources.<br />
<br />
Note to contributers: Please try to keep descriptions short and to the point (approximately 200 words) and avoid long lists of features or capabilities. Also keep in mind that all contributions are considered to be released under the GNU Free Documentation License 1.2 (see [[Project:Copyrights]] for details). <br />
<br />
== Free codes ==<br />
<br />
This section lists codes that are in the public domain, and codes that are available under GPL, BSD or similar licenses.<br />
<br />
=== Solvers ===<br />
<br />
* ADFC -- [http://adfc.sourceforge.net/index.html ADFC homepage]<br />
* Diagonalized Upwind Navier Stokes -- [http://duns.sourceforge.net DUNS homepage]<br />
* Dolfyn -- [http://www.dolfyn.net/dolfyn/index_en.html dolfyn homepage]<br />
*[[Edge]] -- [http://www.edge.foi.se/ Edge homepage]<br />
*[[ELMER]] -- [http://www.csc.fi/elmer/ ELMER homepage]<br />
* Featflow -- [http://www.featflow.de Featflow homepage]<br />
* Femwater -- [http://www.cee.odu.edu/model/femwater.php Femwater code]<br />
* FreeFEM -- [http://www.freefem.org FreeFEM homepage]<br />
*[[Gerris Flow Solver]] -- [http://gfs.sourceforge.net/ Gerris Flow Solver homepage]<br />
* IMTEK Mathematica Supplement (IMS) -- [http://www.imtek.uni-freiburg.de/simulation/mathematica/IMSweb/ IMTEK Mathematica Supplement (IMS) homepage]<br />
* iNavier -- [http://inavier.sourceforge.net/ iNavier Solver Home Page]<br />
* MFIX -- [http://www.mfix.org Computational multiphase flow homepage]<br />
*[[NaSt2D-2.0]] -- [http://home.arcor.de/drklaus.bauerfeind/nast/eNaSt2D.html NaSt2D-2.0 homepage]<br />
*[[NSC2KE]] -- [http://www-rocq1.inria.fr/gamma/cdrom/www/nsc2ke/eng.htm NSC2KE homepage]<br />
*[[OpenFlower]] -- [http://sourceforge.net/projects/openflower/ OpenFlower homepage]<br />
*[[OpenFOAM]] -- [http://www.openfoam.org/ OpenFOAM homepage]<br />
* OpenFVM -- [http://openfvm.sourceforge.net/ OpenFVM homepage]<br />
* PETSc-FEM -- [http://www.cimec.org.ar/petscfem PETSc-FEM homepage]<br />
* PP3D -- [http://www.featflow.de/ parpp3d++ homepage]<br />
* SLFCFD -- [http://slfcfd.sourceforge.net SLFCFD homepage]<br />
*[[SSIIM]] -- [http://folk.ntnu.no/nilsol/cfd/ CFD at NTNU]<br />
*[[Tochnog]] -- [http://tochnog.sourceforge.net Tochnog homepage]<br />
* Typhon solver -- [http://typhon.sf.net Typhon solver homepage]<br />
<br />
=== Grid generation ===<br />
<br />
*[[Delaundo]] -- [http://www.cerfacs.fr/~muller/delaundo.html Delaundo homepage]<br />
* GMSH -- [http://www.geuz.org/gmsh/ GMSH hompage]<br />
* NETGEN -- [http://www.hpfem.jku.at/netgen/ NETGEN homepage]<br />
* SALOME -- [http://www.salome-platform.org SALOME homepage]<br />
* TETGEN -- [http://tetgen.berlios.de/ TETGEN hompage]<br />
*[[Triangle]] -- [http://www.cs.cmu.edu/~quake/triangle.html Triangle homepage]<br />
<br />
=== Visualization ===<br />
*[[DISLIN]] -- [http://www.mps.mpg.de/dislin/server.html DISLIN homepage]<br />
* GMV -- [http://www-xdiv.lanl.gov/XCM/gmv/ GMV homepage]<br />
*[[Gnuplot]] -- [http://www.gnuplot.info/ gnuplot homepage]<br />
* GRI -- [http://gri.sourceforge.net/ GRI homepage]<br />
*[[Mayavi]] -- [http://mayavi.sourceforge.net/ MayaVi homepage]<br />
*[[OpenDX]] <br />
*[[ParaView]] -- [http://www.paraview.org/HTML/Index.html ParaView homepage]<br />
*[[Tioga]] -- [http://www.kitp.ucsb.edu/~paxton/tioga.html Tioga homepage]<br />
*[[Vigie]] -- [http://www-sop.inria.fr/sinus/Softs/vigie.html Vigie homepage]<br />
*[[Visit]]<br />
*[[vtk]] -- [http://www.vtk.org vtk homepage]<br />
*[[vtk.Net]] -- [http://vtkdotnet.sourceforge.net/ vtk.Net homepage]<br />
<br />
=== Miscellaneous ===<br />
<br />
*[[Engauge Digitizer]]<br />
*[[Ftnchek]]<br />
*[[g3data]] -- [http://www.frantz.fi/index.php?page=software g3data homepage]<br />
*[[GIFMerge]] -- [http://www.the-labs.com/GIFMerge/ GIFMerge homepage]<br />
*[[Gifsicle]]<br />
<br />
== Commercial codes ==<br />
<br />
=== Solvers ===<br />
<br />
*[[AcuSolve]] -- [http://www.acusim.com/ ACUSIM Software's homepage]<br />
*[[ADINA-F]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[ADINA-FSI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[ANSWER]] -- [http://www.acricfd.com/ ACRi's homepage]<br />
*[http://www.cfd-online.com/W/index.php?title=CFD%2B%2B CFD++] -- [http://www.metacomptech.com Metacomp Techonlogies' homepage]<br />
*[[CFD2000]] -- [http://www.adaptive-research.com/ Adaptive Research's homepage]<br />
*[[CFD-FASTRAN]] -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
*[[CFD-ACE]] -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
*[[CFdesign]] -- [http://www.cfdesign.com CFdesign's homepage]<br />
*[[CFX]] -- [http://www.ansys.com/ Ansys' homepage]<br />
*[[EFD - Engineering Fluid Dynamics]] -- [http://www.nika.biz/ Flomerics/NIKA homepage]<br />
*[[FENSAP-ICE]] -- [http://www.newmerical.com/ NTI' homepage]<br />
*[[FINE]] -- [http://www.numeca.be/ Numeca's homepage]<br />
*[[FIRE]] -- [http://www.avl.com/ AVL's homepage]<br />
*[[FLACS]] -- [http://www.gexcon.com/index.php?src=flacs/overview.html GexCon's homepage]<br />
*[[FLOW-3D]] -- [http://www.flow3d.com/ Flow Science's homepage]<br />
*[[FLOMERICS]]-- {http://www.flomerics.com Flomerics' homepage]<br />
*[[FLOWVISION]] -- [http://www.fv-tech.com FlowVision's homepage]<br />
*[[FLUENT]] -- [http://www.fluent.com Fluent's homepage]<br />
*[[FluSol]] -- [http://www.cfd-rocket.com FluSol's hompage]*[[J-FLO]] -- [http://www.newmerical.com NTI's homepage]<br />
*[[Flowz]]--[http://www.zeusnumerix.com Zeus Numerix's homepage ]<br />
*[[KINetics Reactive Flows]] -- [http://www.ReactionDesign.com Reaction Design's homepage]<br />
*[[KIVA]]--[http://www.lanl.gov/orgs/t/t3/codes/kiva.shtml Los Alamos homepage]<br />
*[[NOGRID FPM]] -- [http://www.no-grid.com NOGRIDS's homepage]<br />
*[[PHOENICS]] -- [http://www.cham.co.uk CHAM's homepage]<br />
*[[SPLASH]] -- [http://www.panix.com/~brosen SPLASH's homepage]<br />
*[[STAR-CD]] -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
*[[STAR-CCMplus]] -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
*[[Turb'Flow]] -- [http://www.fluorem.com Fluorem's hompage]<br />
<br />
=== Grid generation ===<br />
<br />
*[[ADINA-AUI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-GEOM]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFD-VISCART]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFDExpert-GridZ ]] --[http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
*[[Gridgen]] -- [http://www.pointwise.com/ Pointwise's homepage]<br />
*[[GridPro]] -- [http://www.gridpro.com/ PDC's homepage]<br />
*[[Harpoon]] -- [http://www.ensight.com/ CEI's homepage]<br />
*[[ICEM CFD ]] -- [http://www.ansys.com/ ANSYS' homepage]<br />
<br />
=== Visualization ===<br />
<br />
*[[ADINA-AUI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-VIEW]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFX-Post]] -- [http://www.ansys.com/ ANSYS' homepage]<br />
*[[COVISE]] -- [http://www.visenso.de/ Visenso's homepage]<br />
*[[EnSight]] -- [http://www.ensight.com/ CEI's homepage]<br />
*[[Fieldview]] -- [http://www.ilight.com/ Intelligent Light's homepage]<br />
*[[Tecplot]] -- [http://www.tecplot.com/ Tecplot's homepage]<br />
*[[ViewZ]] -- [http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
<br />
=== Systems ===<br />
<br />
*[[ADINA]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[Flownex]] -- [http://www.flownex.com/ Flownex's homepage]<br />
<br />
== Online tools and services ==<br />
<br />
*[[CFDNet]] -- [http://www.cfdnet.com/ CFDNet homepage]</div>Jasondhttp://www.cfd-online.com/Wiki/CodesCodes2007-06-07T17:29:06Z<p>Jasond: /* Grid generation */</p>
<hr />
<div>An overview of both free and commercial CFD software. Here you will find short descriptions of codes along with links to resources.<br />
<br />
Note to contributers: Please try to keep descriptions short and to the point (approximately 200 words) and avoid long lists of features or capabilities. Also keep in mind that all contributions are considered to be released under the GNU Free Documentation License 1.2 (see [[Project:Copyrights]] for details). <br />
<br />
== Free codes ==<br />
<br />
This section lists codes that are in the public domain, and codes that are available under GPL, BSD or similar licenses.<br />
<br />
=== Solvers ===<br />
<br />
* ADFC -- [http://adfc.sourceforge.net/index.html ADFC homepage]<br />
* Diagonalized Upwind Navier Stokes -- [http://duns.sourceforge.net DUNS homepage]<br />
* Dolfyn -- [http://www.dolfyn.net/dolfyn/index_en.html dolfyn homepage]<br />
*[[Edge]] -- [http://www.edge.foi.se/ Edge homepage]<br />
*[[ELMER]] -- [http://www.csc.fi/elmer/ ELMER homepage]<br />
* Featflow -- [http://www.featflow.de Featflow homepage]<br />
* Femwater -- [http://www.cee.odu.edu/model/femwater.php Femwater code]<br />
* FreeFEM -- [http://www.freefem.org FreeFEM homepage]<br />
*[[Gerris Flow Solver]] -- [http://gfs.sourceforge.net/ Gerris Flow Solver homepage]<br />
* IMTEK Mathematica Supplement (IMS) -- [http://www.imtek.uni-freiburg.de/simulation/mathematica/IMSweb/ IMTEK Mathematica Supplement (IMS) homepage]<br />
* iNavier -- [http://inavier.sourceforge.net/ iNavier Solver Home Page]<br />
* MFIX -- [http://www.mfix.org Computational multiphase flow homepage]<br />
*[[NaSt2D-2.0]] -- [http://home.arcor.de/drklaus.bauerfeind/nast/eNaSt2D.html NaSt2D-2.0 homepage]<br />
*[[NSC2KE]] -- [http://www-rocq1.inria.fr/gamma/cdrom/www/nsc2ke/eng.htm NSC2KE homepage]<br />
*[[OpenFlower]] -- [http://sourceforge.net/projects/openflower/ OpenFlower homepage]<br />
*[[OpenFOAM]] -- [http://www.openfoam.org/ OpenFOAM homepage]<br />
* OpenFVM -- [http://openfvm.sourceforge.net/ OpenFVM homepage]<br />
* PETSc-FEM -- [http://www.cimec.org.ar/petscfem PETSc-FEM homepage]<br />
* PP3D -- [http://www.featflow.de/ parpp3d++ homepage]<br />
* SLFCFD -- [http://slfcfd.sourceforge.net SLFCFD homepage]<br />
*[[SSIIM]] -- [http://folk.ntnu.no/nilsol/cfd/ CFD at NTNU]<br />
*[[Tochnog]] -- [http://tochnog.sourceforge.net Tochnog homepage]<br />
* Typhon solver -- [http://typhon.sf.net Typhon solver homepage]<br />
<br />
=== Grid generation ===<br />
<br />
*[[Delaundo]] -- [http://www.cerfacs.fr/~muller/delaundo.html Delaundo homepage]<br />
* GMSH -- [http://www.geuz.org/gmsh/ GMSH hompage]<br />
* NETGEN -- [http://www.hpfem.jku.at/netgen/ NETGEN homepage]<br />
* SALOME -- [http://www.salome-platform.org SALOME homepage]<br />
* TETGEN -- [http://tetgen.berlios.de/ TETGEN hompage]<br />
*[[Triangle]] -- [http://www.cs.cmu.edu/~quake/triangle.html Triangle homepage]<br />
<br />
=== Visualization ===<br />
*[[DISLIN]] -- [http://www.mps.mpg.de/dislin/server.html DISLIN homepage]<br />
*[[GMV]] -- [http://www-xdiv.lanl.gov/XCM/gmv/ GMV homepage]<br />
*[[Gnuplot]] -- [http://www.gnuplot.info/ gnuplot homepage]<br />
*[[GRI]] -- [http://gri.sourceforge.net/ GRI homepage]<br />
*[[Mayavi]] -- [http://mayavi.sourceforge.net/ MayaVi homepage]<br />
*[[OpenDX]] <br />
*[[ParaView]] -- [http://www.paraview.org/HTML/Index.html ParaView homepage]<br />
*[[Tioga]] -- [http://www.kitp.ucsb.edu/~paxton/tioga.html Tioga homepage]<br />
*[[Vigie]] -- [http://www-sop.inria.fr/sinus/Softs/vigie.html Vigie homepage]<br />
*[[Visit]]<br />
*[[vtk]] -- [http://www.vtk.org vtk homepage]<br />
*[[vtk.Net]] -- [http://vtkdotnet.sourceforge.net/ vtk.Net homepage]<br />
<br />
=== Miscellaneous ===<br />
<br />
*[[Engauge Digitizer]]<br />
*[[Ftnchek]]<br />
*[[g3data]] -- [http://www.frantz.fi/index.php?page=software g3data homepage]<br />
*[[GIFMerge]] -- [http://www.the-labs.com/GIFMerge/ GIFMerge homepage]<br />
*[[Gifsicle]]<br />
<br />
== Commercial codes ==<br />
<br />
=== Solvers ===<br />
<br />
*[[AcuSolve]] -- [http://www.acusim.com/ ACUSIM Software's homepage]<br />
*[[ADINA-F]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[ADINA-FSI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[ANSWER]] -- [http://www.acricfd.com/ ACRi's homepage]<br />
*[http://www.cfd-online.com/W/index.php?title=CFD%2B%2B CFD++] -- [http://www.metacomptech.com Metacomp Techonlogies' homepage]<br />
*[[CFD2000]] -- [http://www.adaptive-research.com/ Adaptive Research's homepage]<br />
*[[CFD-FASTRAN]] -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
*[[CFD-ACE]] -- [http://www.esi-group.com/SimulationSoftware/advanced.html ESI Group's homepage]<br />
*[[CFdesign]] -- [http://www.cfdesign.com CFdesign's homepage]<br />
*[[CFX]] -- [http://www.ansys.com/ Ansys' homepage]<br />
*[[EFD - Engineering Fluid Dynamics]] -- [http://www.nika.biz/ Flomerics/NIKA homepage]<br />
*[[FENSAP-ICE]] -- [http://www.newmerical.com/ NTI' homepage]<br />
*[[FINE]] -- [http://www.numeca.be/ Numeca's homepage]<br />
*[[FIRE]] -- [http://www.avl.com/ AVL's homepage]<br />
*[[FLACS]] -- [http://www.gexcon.com/index.php?src=flacs/overview.html GexCon's homepage]<br />
*[[FLOW-3D]] -- [http://www.flow3d.com/ Flow Science's homepage]<br />
*[[FLOMERICS]]-- {http://www.flomerics.com Flomerics' homepage]<br />
*[[FLOWVISION]] -- [http://www.fv-tech.com FlowVision's homepage]<br />
*[[FLUENT]] -- [http://www.fluent.com Fluent's homepage]<br />
*[[FluSol]] -- [http://www.cfd-rocket.com FluSol's hompage]*[[J-FLO]] -- [http://www.newmerical.com NTI's homepage]<br />
*[[Flowz]]--[http://www.zeusnumerix.com Zeus Numerix's homepage ]<br />
*[[KINetics Reactive Flows]] -- [http://www.ReactionDesign.com Reaction Design's homepage]<br />
*[[KIVA]]--[http://www.lanl.gov/orgs/t/t3/codes/kiva.shtml Los Alamos homepage]<br />
*[[NOGRID FPM]] -- [http://www.no-grid.com NOGRIDS's homepage]<br />
*[[PHOENICS]] -- [http://www.cham.co.uk CHAM's homepage]<br />
*[[SPLASH]] -- [http://www.panix.com/~brosen SPLASH's homepage]<br />
*[[STAR-CD]] -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
*[[STAR-CCMplus]] -- [http://www.cd-adapco.com CD-adapco's homepage]<br />
*[[Turb'Flow]] -- [http://www.fluorem.com Fluorem's hompage]<br />
<br />
=== Grid generation ===<br />
<br />
*[[ADINA-AUI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-GEOM]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFD-VISCART]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFDExpert-GridZ ]] --[http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
*[[Gridgen]] -- [http://www.pointwise.com/ Pointwise's homepage]<br />
*[[GridPro]] -- [http://www.gridpro.com/ PDC's homepage]<br />
*[[Harpoon]] -- [http://www.ensight.com/ CEI's homepage]<br />
*[[ICEM CFD ]] -- [http://www.ansys.com/ ANSYS' homepage]<br />
<br />
=== Visualization ===<br />
<br />
*[[ADINA-AUI]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[CFD-VIEW]] -- [http://www.esi-group.com/ ESI's homepage]<br />
*[[CFX-Post]] -- [http://www.ansys.com/ ANSYS' homepage]<br />
*[[COVISE]] -- [http://www.visenso.de/ Visenso's homepage]<br />
*[[EnSight]] -- [http://www.ensight.com/ CEI's homepage]<br />
*[[Fieldview]] -- [http://www.ilight.com/ Intelligent Light's homepage]<br />
*[[Tecplot]] -- [http://www.tecplot.com/ Tecplot's homepage]<br />
*[[ViewZ]] -- [http://www.zeusnumerix.com/ Zeus Numerix's homepage]<br />
<br />
=== Systems ===<br />
<br />
*[[ADINA]] -- [http://www.adina.com/index.html ADINA's homepage]<br />
*[[Flownex]] -- [http://www.flownex.com/ Flownex's homepage]<br />
<br />
== Online tools and services ==<br />
<br />
*[[CFDNet]] -- [http://www.cfdnet.com/ CFDNet homepage]</div>Jasond