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Old   April 15, 2014, 09:38
Smile OpenFoam/Tutorial problems/heatexchanger
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Hello Dear members of CFD Online,

my Name is Markus and Iam a new user from OpenFoam. I downloaded the processing
system Ubuntu and after OpenFoam.

I am having many Problems with my first steps and hope, everyone can help me!

1) about Tutorial heatexchanger

If I try the running of the blockMesh, then I get the mistake -->

sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Disallowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time


--> FOAM FATAL IO ERROR:
cannot find file

file: /home/markusl/OpenFOAM/tutor-heatexchanger/run/system/controlDict at line 0.

From function regIOobject::readStream()
in file db/regIOobject/regIOobjectRead.C at line 73.

FOAM exiting


Unfortunately, I don't understand this mistake! What I am doing wrong?

2) about Tutorial circuitBoardCooling

The BlockMesh works, but the solver ( buoyantSimpleFoam is in the controldict ) don't running and I get the mistake -->

Create time

Create mesh for time = 0


Reading g
Reading thermophysical properties

Selecting thermodynamics package
{
type heRhoThermo;
mixture pureMixture;
transport const;
thermo hConst;
equationOfState perfectGas;
specie specie;
energy sensibleEnthalpy;
}



--> FOAM FATAL IO ERROR:
cannot find file

file: /home/markusl/OpenFOAM/tutor-baffels/run/circuitBoardCooling/0/p at line 0.

From function regIOobject::readStream()
in file db/regIOobject/regIOobjectRead.C at line 73.

FOAM exiting


I hope really the users in the forum can me help and write a short answer!


Thank you


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Old   April 15, 2014, 14:48
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Quote:
Originally Posted by 12Markus12 View Post
Hello Dear members of CFD Online,

my Name is Markus and Iam a new user from OpenFoam. I downloaded the processing
system Ubuntu and after OpenFoam.

I am having many Problems with my first steps and hope, everyone can help me!

1) about Tutorial heatexchanger

If I try the running of the blockMesh, then I get the mistake -->

sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Disallowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time


--> FOAM FATAL IO ERROR:
cannot find file

file: /home/markusl/OpenFOAM/tutor-heatexchanger/run/system/controlDict at line 0.

From function regIOobject::readStream()
in file db/regIOobject/regIOobjectRead.C at line 73.

FOAM exiting


Unfortunately, I don't understand this mistake! What I am doing wrong?
Hello and wellcome Markus!

First of all, I don't think it's a good idea to start "playing" with OF with this tutorial. Have you fully read the User's Guide and practiced with the tutorials shown there? If so, then I suggest you to practice with another multi-region tutorial which is simpler than heatExchanger and it is explained here:

http://openfoamwiki.net/index.php/Ge..._-_planeWall2D

Here you will see that in the case of a multi-region problem you have to take some more steps to solve the problem. Another advice I can give you is to open the Allrun file to see the extra steps you have to take in your case...

I hope you enjoy reading and "playing" with the planeWall2D tutorial like I did!

Alex
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Old   April 16, 2014, 05:34
Default Thank you
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Hello Alex.

Thank you for you description. I am very happy for your help.

I had read the User Guid and did run the tutorials.
But, if I went to the site,
P { margin-bottom: 0.21cm; }A:link { }http://openfoamwiki.net/index.php/Ge..._-_planeWall2D
unpacked it and want running the program with the

folder -- ./Allrun -- then nothing happens and I don't know why??!!


I have this problem with other tutorials too.


Could you help me about this problem,please?




Markus














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Old   April 16, 2014, 07:17
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What do you exactly mean when you say that "nothing happens"? Any error message? Are you executing the ./Allrun command in the terminal from within the case directory? Which is your OF version? If you have v.2.2.x or higher you have to download the planeWall2D-2.2.tar.gz file instead planeWall2D.tar.gz.

Regards,

Alex
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Old   April 16, 2014, 07:38
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I am working with the version OF Ubuntu Deb Pack version 2.3.0 and I give the command Allrun in the Termina for example:
MacBookPro:~/OpenFOAM/planeWall2D$ Allrun --> enter --> and the result is Command not found

My sencond try was double-click on Allrun in the folder --> run in the Terminal / Yes --> and the result is, the Terminal will open and close again.

So it is with each tutorial

Best regards,

Markus
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Old   April 16, 2014, 07:47
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The command you have to exceute is ./Allrun not only Allrun!
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The case I talk about in this site was solved with chtMultiRegionSimpleFoam solver and involves radiation. Some basic tutorials are also resolved step by step in the web. If you are interested in these matters, you are invited to come in!
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Old   April 16, 2014, 07:49
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Which is explained in the tutorial web site I posted above... You didn't pay much attention on that!
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Old   April 16, 2014, 07:52
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Another example Alex

I try the OpenFoam tutorial circuitBoardCooling

1. I give in the Terminal
MacBookPro:~/OpenFOAM/tutor-baffels/run/circuitBoardCooling$
2. blockMesh --> is calculated
3. If I enter the solver buoyantSimpleFoam, which is in the controlDict then happens this mistake

/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.3.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 2.3.0-f5222ca19ce6
Exec : buoyantSimpleFoam
Date : Apr 16 2014
Time : 13:45:38
Host : "markusl-MacBookPro"
PID : 10495
Case : /home/markusl/OpenFOAM/tutor-baffels/run/circuitBoardCooling
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Disallowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0


Reading g
Reading thermophysical properties

Selecting thermodynamics package
{
type heRhoThermo;
mixture pureMixture;
transport const;
thermo hConst;
equationOfState perfectGas;
specie specie;
energy sensibleEnthalpy;
}



--> FOAM FATAL IO ERROR:
cannot find file

file: /home/markusl/OpenFOAM/tutor-baffels/run/circuitBoardCooling/0/p at line 0.

From function regIOobject::readStream()
in file db/regIOobject/regIOobjectRead.C at line 73.

FOAM exiting



regards,

Markus
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Old   April 16, 2014, 07:58
Default ./Allrun not Allrun!!!!
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This error is easy Markus, you haven't set up the p-file in the /case/o/ folder or it was incorrectly set up. Review this file. Besides that, try to execute the ./Allrun command, because you have to take some other steps before runing the solver in this tutorial I guess...


Regards,


Alex
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The case I talk about in this site was solved with chtMultiRegionSimpleFoam solver and involves radiation. Some basic tutorials are also resolved step by step in the web. If you are interested in these matters, you are invited to come in!
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Old   April 16, 2014, 09:04
Default command ./Allrun
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I have set up the p-file in the /case/o/ folder, but with the command ./Allrun is the program running - Thank you Alex.


The command ./Allrun execute the complete program or only the mesh, because if I open paraFoam then can I saw only the mesh???


Thank you for your help and support


regards,

Markus

P { margin-bottom: 0.21cm; }A:link { }
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Old   April 16, 2014, 09:29
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The command ./Allrun executes all the applications you need to solve the case. You can open it with a text editor and see all the applications run when you execute the command. When you open paraView by executing the paraFoam command in the Terminal you have to open all the files created (3 files in the planeWall2D case, for instance). By default, you only open the main file when executing paraFoam (planeWall2D.OpenFOAM), but you need to open the rest of the files created, these are:
  • planeWall2D{bottomAir}.OpenFOAM
  • planeWall2D{topAir}.OpenFOAM
  • planeWall2D{wall}.OpenFOAM

Once you have opened these files you can see the calculations done in each region!

Regards,

Alex
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The case I talk about in this site was solved with chtMultiRegionSimpleFoam solver and involves radiation. Some basic tutorials are also resolved step by step in the web. If you are interested in these matters, you are invited to come in!
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Old   April 16, 2014, 10:12
Default Solver is missing?
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I created all the files enclosed,

Running chtMultiRegionSimpleFoam on /home/markusl/OpenFOAM/planeWall2D

creating files for paraview post-processing

created 'planeWall2D.blockMesh'
created 'planeWall2D.OpenFOAM'
created 'planeWall2D{bottomAir}.OpenFOAM'
created 'planeWall2D{topAir}.OpenFOAM'
created 'planeWall2D{wall}.OpenFOAM'


after I showed it in paraFoam.
Unfortunately I think the solver is missing, because I am having a short calculation time and not different sections. Furthermore the geometry is parallel, because it hasn't a higher region.

Do you have answers for my questions?


regards,

Markus
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Old   April 16, 2014, 15:05
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Quick answer: The "planeWall2D" tutorial available on the wiki has not yet been updated to work with OpenFOAM 2.3.0.
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Old   April 17, 2014, 15:15
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Quote:
Originally Posted by wyldckat View Post
Quick answer: The "planeWall2D" tutorial available on the wiki has not yet been updated to work with OpenFOAM 2.3.0.
Thanks for the info Bruno!
@Markus, now you know how to proceed with the rest of the multi region tutorials
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Old   April 20, 2014, 15:00
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Quote:
Originally Posted by wyldckat View Post
Quick answer: The "planeWall2D" tutorial available on the wiki has not yet been updated to work with OpenFOAM 2.3.0.
Another quick answer: I've uploaded the adapted tutorial for OpenFOAM 2.3, with some additional changes, based on the changes made on the OpenFOAM tutorials: http://openfoamwiki.net/index.php/Ge..._-_planeWall2D
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Old   April 22, 2014, 03:14
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Thank you Alex and Bruno for your help!

regards,

Markus
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Old   June 17, 2015, 18:10
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Hi Bruno.
I noticed different results when going from OF2.2 to OF2.3.
The main one is the velocity and pressure field.
In 2.3 the velocity increases by one order of magnitude at the very first cell and it seems due to the wrong boundary conditions: both velocity and pressure (p_rgh) are specified at the inlet.
I don't understand why this doesn't happen with OF2.2, where same boundary conditions are used.
I used the files available in the wiki page
https://openfoamwiki.net/index.php/G..._-_planeWall2D
without modifications.
Attached are the temperature, pressure ant velocity with 2.3.
I also tried to run the 2.2 case adapted to 2.3 (the only changes were to change the entry for T in changeDictionaryDict from neighbourFieldName to Tnbr and add the term (rhorAuf, prgh) in the laplacian of fvSchemes for bottomAir and topAir, but same results are obtained.
If you guys have an idea of what I am missing please let me know.
Attached Images
File Type: jpg u_x.jpg (12.1 KB, 24 views)
File Type: jpg T.jpg (12.7 KB, 24 views)
File Type: jpg p.jpg (14.1 KB, 20 views)
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Old   August 18, 2015, 21:07
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Greetings Daniele,

Sorry for the late reply, but only today did I finally managed to look into this.

Before I forget, this thread has some more details on boundary conditions that might not be all that correct: http://www.cfd-online.com/Forums/ope...tml#post539022 - post #6 and onwards... in post #15 are some clarification on some of the details about this tutorial case.

Now, as for the issue you've pointed out, there is another important detail on how the cases for 2.2 and 2.3 were configured: a lot of changes were made in the file "system/fvSchemes", most of which rely in 2.3 in 2nd order schemes (linear) instead of 1st order (upwind), as well as "corrected" instead of "uncorrected" in some other cases. This kind of thing is enough to bring a lot of changes to the results.
The other detail is that "system/controlDict" has different settings for the "endTime", with "50000" in 2.2 vs "10000" in 2.3.

Nonetheless, as you reported, looks like these changes to the schemes and "controlDict" were not what made the results so different.

After a bit of testing, I rediscovered why I defined the inlet to have both the pressure and velocity: because the pressure boundaries are all defined to be "fixedFluxPressure", so that they respect the influence of buoyancy/gravity. If we define the fixed pressure "p_rgh" on the outlet, the "topAir" region will have a weird recirculation profile. The interesting detail is that in this set-up, the case is nearly identical with OpenFOAM 2.2 and 2.3.

As for the weird velocity profile you pointed out, that seems to be also related to the pressure fields, but due to another reason. In 2.3.0 was introduced this block of code in "applications/solvers/heatTransfer/chtMultiRegionFoam/chtMultiRegionSimpleFoam/fluid/pEqn.H":
Code:
    // Update the fixedFluxPressure BCs to ensure flux consistency
    setSnGrad<fixedFluxPressureFvPatchScalarField>
    (
        p_rgh.boundaryField(),
        (
            phiHbyA.boundaryField()
          - fvOptions.relative(mesh.Sf().boundaryField() & U.boundaryField())
           *rho.boundaryField()
        )/(mesh.magSf().boundaryField()*rhorAUf.boundaryField())
    );
This enforces a rebalancing of the pressure fields, which wasn't done in 2.2.x. This means that this enforcement is done on the boundary condition "fixedFluxPressure", which is used in the "planeWall2D" tutorial but only fully enforced as of 2.3.0. Since the pressure balance is thrown a bit off, this leads to the speed jump you've pointed out.

Although... this is weird... we're fixing the pressure value in the inlet or outlet in the "p_rgh" field, not in the "p" field, so this shouldn't matter as much...


OK, I didn't figure this out in one go. I'll try to figure this out within the next 24h hours.

Best regards,
Bruno
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