CFD Online Discussion Forums - OpenFOAM Running / Solving / CFD http://www.cfd-online.com/Forums/ en Wed, 08 Sep 2010 12:30:20 GMT vBulletin 60 http://www.cfd-online.com/Forums/images/misc/rss.jpg CFD Online Discussion Forums - OpenFOAM Running / Solving / CFD http://www.cfd-online.com/Forums/ forces and symmetryPlane http://www.cfd-online.com/Forums/openfoam-solving/79879-forces-symmetryplane.html Tue, 07 Sep 2010 15:04:06 GMT Hi Foamers, a short question: if i use a halfmodel with a symmetryPlane cutting it, do i take the projected area of the full model or of the half... Hi Foamers,

a short question: if i use a halfmodel with a symmetryPlane cutting it, do i take the projected area of the full model or of the half model for the forces in controlDict?

Thanks for your help :)!
Moritz ]]> OpenFOAM Running / Solving / CFD Mo-ITB http://www.cfd-online.com/Forums/openfoam-solving/79879-forces-symmetryplane.html BuoyantBoussinesqPisoFoam - laminar http://www.cfd-online.com/Forums/openfoam-solving/79878-buoyantboussinesqpisofoam-laminar.html Tue, 07 Sep 2010 14:30:47 GMT Hi people
I don't understand one thing about this solver:
buoyantBoussinesqPisoFoam solver is based on RANS, it is correct?
but when I select laminar in RASmodel, it means it used a particular turbulence model useful for laminar flow?

because I need to simulate some cases of natural convection....


thank you all:)


Fabio ]]> OpenFOAM Running / Solving / CFD Fabio88 http://www.cfd-online.com/Forums/openfoam-solving/79878-buoyantboussinesqpisofoam-laminar.html two mixing compresible fluids solver http://www.cfd-online.com/Forums/openfoam-solving/79875-two-mixing-compresible-fluids-solver.html Tue, 07 Sep 2010 13:32:52 GMT Hi, I am interested in solver which is able to model mixing of two compressible fluids (lets say Helium and Air). As far as I know there is no such... Hi,
I am interested in solver which is able to model mixing of two compressible fluids (lets say Helium and Air).
As far as I know there is no such solver among standard OF solvers.
I looked at twoMixingLiquidFoam which is for incompressible fluids.
So I decided to change this solver for compressible fluids as well, but I am not sure if method used there can be applied for compressible fluids as well.

I am not sure if the concentration equation method from incompressible solver can be used for compressible flows.

My idea is as follows:
1. solve compressible NS eq with PISO method (U,p)
2. solve energy eq (e)
3. solve concentration eq (c)
4. calculate density rho=c*rho1 + (1-c)*rho2
5. similar for viscosity, R (individual gas constant), Cp,...

Could anyone tell me please if such approach is correct ?

Many thanks,
ZM ]]> OpenFOAM Running / Solving / CFD ziemowitzima http://www.cfd-online.com/Forums/openfoam-solving/79875-two-mixing-compresible-fluids-solver.html How to implement this new model in OpenFOAM1.7.1 ? http://www.cfd-online.com/Forums/openfoam-solving/79873-how-implement-new-model-openfoam1-7-1-a.html Tue, 07 Sep 2010 12:28:40 GMT Hi,
I need help, please?

I am new to OpenFOAM,
I have a new model,
and i need to know how exactly "to write in text the equations 1 and 2" to solve them ( in cylindrical coord)
see the attached jpeg file

Thanks a lot.
Attached Images
File Type: jpg MyModel.JPG (39.8 KB)
]]> OpenFOAM Running / Solving / CFD T.D. http://www.cfd-online.com/Forums/openfoam-solving/79873-how-implement-new-model-openfoam1-7-1-a.html For loops in OpenFoam http://www.cfd-online.com/Forums/openfoam-solving/79840-loops-openfoam.html Mon, 06 Sep 2010 11:54:42 GMT I am generalising the twoPhase Euler Foam to handle n Phases . In the file pEqn.H I want to sum up the phase fraction of all the dispersed phases to... I am generalising the twoPhase Euler Foam to handle n Phases . In the file pEqn.H I want to sum up the phase fraction of all the dispersed phases to get the dispersed phase . To do so I programmed the following :
Code:
PtrList<surfaceScalarField>alphaf(nPhases);                                                                                             
                                                                                                                                             
    //just an initialization                                                                                                                 
    surfaceScalarField af ;                                                                                                                 
    surfaceScalarField betaf = scalar(1) - af;                                                                                               
                                                                                                                                             
    forAll(alphaf,aPh)                                                                                                                       
    {                                                                                                                                       
        alphaf.set(aPh,fvc::interpolate(phases[aPh].alpha()));                                                                               
        af= af + alphaf[aPh];                                                                                                               
    }                                                                                                                                       
    betaf = scalar(1) - af ;
On compilation I got the following error :
Code:
error: no matching function for call to ‘Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh>::GeometricField()’
/home/ifmg/OpenFOAM/OpenFOAM-1.7.0/src/OpenFOAM/lnInclude/GeometricField.C:652: note: candidates are: Foam::GeometricField<Type, PatchField, GeoMesh>::GeometricField(const Foam::IOobject&, const Foam::GeometricField<Type, PatchField, GeoMesh>&, const Foam::wordList&) [with Type = double, PatchField = Foam::fvsPatchField, GeoMesh = Foam::surfaceMesh]
]]> OpenFOAM Running / Solving / CFD balkrishna http://www.cfd-online.com/Forums/openfoam-solving/79840-loops-openfoam.html Thin Wall Heat Transfer BC for rhoSimpleFoam http://www.cfd-online.com/Forums/openfoam-solving/79824-thin-wall-heat-transfer-bc-rhosimplefoam.html Mon, 06 Sep 2010 02:18:58 GMT Good afternoon everyone!

I'm just starting to look at using OpenFOAM to solve a heat transfer problem across a 'thin' (thickness approaching zero) wall in a high Re compressible flow.
I am using the rhoSimpleFoam solver, and I don't currently have a separate solid mesh for the wall.

I have problem with specifying a wall BC for temperature that will solve the heat transfer across a thin wall (conjugate fluid-solid heat transfer) without having a separate mesh for the solid.

Specifying zeroGradient BC at the wall led to the wall being treated as an adiabatic wall.
The appropriate temperature BC at the wall should be constant heat flux across the wall.

I think Fluent does the heat transfer across the wall somehow by creating the 'shadow' wall, and then mapping the temperature on one side to the other side of the wall, and solve using an outer iteration to satisfy the constant heat flux condition across the wall.

Can anyone please help me if there is already an existing BC with OF that does this?

Thank you very much for your help.

Best regards,
Stefano ]]> OpenFOAM Running / Solving / CFD swahono http://www.cfd-online.com/Forums/openfoam-solving/79824-thin-wall-heat-transfer-bc-rhosimplefoam.html Turbulence model for mixing problem http://www.cfd-online.com/Forums/openfoam-solving/79807-turbulence-model-mixing-problem.html Sat, 04 Sep 2010 23:53:09 GMT Hello all, I am trying to simulate the air/fuel mixing in a combustion chamber. For this i need to use some turbulence model (RANS). 1) Which... Hello all,

I am trying to simulate the air/fuel mixing in a combustion chamber. For this i need to use some turbulence model (RANS).

1) Which model would be better suited for such kind of simulation?? RNG-k-eps or SST-kW or any other??

2) About near wall treatment: I suppose k-w does not need a wall function in OF as it is already hard coded, am i right??

3) For RNG k-eps i will have to give some near wall function. Now my dialemma is for coarse mesh (y+ > 30) i have to specify wall function if i use standard k-eps model (which is High Re model in OF). But what if i use Low Re model like Launder-Sharma?? What about RNG (is it low Re or high Re)??

4) For mixing problem like this, how much importance the "near wall flow" have??? I am currently doing only cold flow simulations. ]]> OpenFOAM Running / Solving / CFD nileshjrane http://www.cfd-online.com/Forums/openfoam-solving/79807-turbulence-model-mixing-problem.html Variable thermophysical property for incompressible flow http://www.cfd-online.com/Forums/openfoam-solving/79706-variable-thermophysical-property-incompressible-flow.html Wed, 01 Sep 2010 05:21:41 GMT Hi foamers, I am solving for a water flow through a cooler in which it experiences a large temperature drop. I tried to look for a way to... Hi foamers,

I am solving for a water flow through a cooler in which it experiences a large temperature drop. I tried to look for a way to implement the changeable thermophysical property of water. For the viscosity, it seems there is one only viscosity model for water, i.e., Newtonian.

In this forum I could also find some threads which are about to solve it in a compressible way. I am not sure about which way I should follow.

Thanks for any suggestion or discussion. ]]> OpenFOAM Running / Solving / CFD JinBiao http://www.cfd-online.com/Forums/openfoam-solving/79706-variable-thermophysical-property-incompressible-flow.html InterMixingFoam - Gravity Currents (not working) http://www.cfd-online.com/Forums/openfoam-solving/79703-intermixingfoam-gravity-currents-not-working.html Wed, 01 Sep 2010 03:42:20 GMT Hi

I'm trying to test the interMixingFoam solver when studing gravity currents. So I took the tutorial example but changing the initial alpha fields. The initial condition is a horizontal free surface, and two separated phases, with different densities (I attach the whole example).

I was expecting to see the gravity currents due the difference in density, but both liquid phases behave as they have the same properties.

What could it be wrong?

Thanks!

Martin
Attached Files
File Type: zip damBreak_GravityCurrents.zip (81.7 KB)
]]> OpenFOAM Running / Solving / CFD msabger http://www.cfd-online.com/Forums/openfoam-solving/79703-intermixingfoam-gravity-currents-not-working.html Running rhoCentralFoam without specification of Temperature http://www.cfd-online.com/Forums/openfoam-solving/79691-running-rhocentralfoam-without-specification-temperature.html Tue, 31 Aug 2010 14:39:28 GMT Hello! I wanted to ask if the specification of temperature is necessary for simulation of pressurization with rhoCentralFoam or if there is a way... Hello!

I wanted to ask if the specification of temperature is necessary for simulation of pressurization with rhoCentralFoam or if there is a way not to specify it.

Thanks in advance! ]]> OpenFOAM Running / Solving / CFD shangzung http://www.cfd-online.com/Forums/openfoam-solving/79691-running-rhocentralfoam-without-specification-temperature.html Negative Total Pressure in cavitatingFoam RAS/Throttle Case in OF 1.6 http://www.cfd-online.com/Forums/openfoam-solving/79664-negative-total-pressure-cavitatingfoam-ras-throttle-case-1-6-a.html Mon, 30 Aug 2010 19:59:39 GMT I'm working on modelling cavitating flow in a series of control valves, and my plan was to use cavitatingFoam to do so. However, when running the "Throttle" tutorial case in the "RAS" subfolder, I noticed that the total pressures (calculated using ptot utility) go negative which seems unphysical. I know that in some other CFD solvers there is a reference pressure somewhere, does OpenFOAM use anything similar? If not, can somebody explain why the negative pressure shows up? ]]> OpenFOAM Running / Solving / CFD danishdude http://www.cfd-online.com/Forums/openfoam-solving/79664-negative-total-pressure-cavitatingfoam-ras-throttle-case-1-6-a.html BubbleFoam http://www.cfd-online.com/Forums/openfoam-solving/79658-bubblefoam.html Mon, 30 Aug 2010 15:45:27 GMT Hi everyone, I am using bubbleFoam to misluate a bubble column, I want to use the tutorial example but simulate the turbulent flow, anyone can give... Hi everyone, I am using bubbleFoam to misluate a bubble column, I want to use the tutorial example but simulate the turbulent flow, anyone can give me some hints on doing that? Thanks. ]]> OpenFOAM Running / Solving / CFD Yas http://www.cfd-online.com/Forums/openfoam-solving/79658-bubblefoam.html Error using GroobyBC http://www.cfd-online.com/Forums/openfoam-solving/79653-error-using-groobybc.html Mon, 30 Aug 2010 13:58:22 GMT Hello,

I'm trying to use GroovyBC to implement following boundary on the velocity field:

PHP Code:
feed
    {
        type            groovyBC;
        variables       "pFeed@feed=p;pDraw@draw=p;";
        valueExpression "(pFeed-pDraw)*normal()";
        value           uniform (0 0 0);        
    }

    draw
    {
        type            fixedValue;
        variables       "pFeed@feed=p;pDraw@draw=p;";
        valueExpression "(pFeed-pDraw)*normal()";
        value           uniform (0 0 0);        
    } 
However, when trying to use icoFoam to solve my problem, I get following error:

PHP Code:
Courant Number mean: 0 max: 2e-05
DILUPBiCG:  Solving for Ux, Initial residual = 1, Final residual = 3.1531e-07, No Iterations 4
DILUPBiCG:  Solving for Uy, Initial residual = 0, Final residual = 0, No Iterations 0
DICPCG:  Solving for p, Initial residual = 1, Final residual = 9.95444e-07, No Iterations 257
time step continuity errors : sum local = 2.58366e-13, global = 9.29505e-16, cumulative = 9.29505e-16
--> FOAM Warning : 
    From function PatchResult::getUniformInternal(const label size,bool noWarn)
    in file PatchResultI.H at line 96
    The minimum value 53.321 and the maximum 1346.83 differ. I will use the average 687.19
DICPCG:  Solving for p, Initial residual = 0.999897, Final residual = 8.51967e-07, No Iterations 260
time step continuity errors : sum local = 8.51066e-09, global = 1.06309e-11, cumulative = 1.06318e-11
--> FOAM Warning : 
    From function PatchResult::getUniformInternal(const label size,bool noWarn)
    in file PatchResultI.H at line 96
    The minimum value -2.21757e+09 and the maximum -3.40424e+08 differ. I will use the average -1.63456e+09
ExecutionTime = 1.1 s  ClockTime = 1 s 
Is it that I cannot access the pressure fields in this way, or why is it happening? ]]> OpenFOAM Running / Solving / CFD NewFoamer http://www.cfd-online.com/Forums/openfoam-solving/79653-error-using-groobybc.html consult some questions about the interPhaseChangeFoam http://www.cfd-online.com/Forums/openfoam-solving/79636-consult-some-questions-about-interphasechangefoam.html Mon, 30 Aug 2010 05:26:25 GMT Hello,everyone:

I'm very interested in the cavitation flow around airfoil. Furthermore, I want to use the interPhaseChangeFoam solver in the directory of application. But I can't understand how to set the three files of 0、constant and system ? Could you give me some advice about it? Or some Tutorials about the cavitaion flow.
thank you very much! ]]> OpenFOAM Running / Solving / CFD super http://www.cfd-online.com/Forums/openfoam-solving/79636-consult-some-questions-about-interphasechangefoam.html Error in recompiling the solver http://www.cfd-online.com/Forums/openfoam-solving/79612-error-recompiling-solver.html Sat, 28 Aug 2010 18:14:42 GMT Hello everyone , i did a few changes in the solver mdfoam.c and when i try to recompile it i encounter this error which i dont know what it is ... Hello everyone ,
i did a few changes in the solver mdfoam.c and when i try to recompile it i encounter this error which i dont know what it is

HTML Code:
mehdi@mehdi-laptop:~/OpenFOAM/OpenFOAM-1.6/applications/solvers/discreteMethods/molecularDynamics/mdFoam$ wclean libso
wclean ./
mehdi@mehdi-laptop:~/OpenFOAM/OpenFOAM-1.6/applications/solvers/discreteMethods/molecularDynamics/mdFoam$ wmake
Making dependency list for source file mdFoam.C
SOURCE=mdFoam.C ;  g++ -m32 -Dlinux -DWM_DP -Wall -Wno-strict-aliasing -Wextra -Wno-unused-parameter -Wold-style-cast -O3  -DNoRepository -ftemplate-depth-40 -I/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude -I/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/potential/lnInclude -I/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecularMeasurements/lnInclude -I/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/finiteVolume/lnInclude -I/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/basic/lnInclude -I/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/meshTools/lnInclude -IlnInclude -I. -I/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/OpenFOAM/lnInclude -I/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/OSspecific/POSIX/lnInclude  -fPIC -c $SOURCE -o Make/linuxGccDPOpt/mdFoam.o
In file included from mdFoam.C:50:
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H: In function ‘int main(int, char**)’:
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:5: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:11: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:17: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:23: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:37: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:43: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:52: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:92: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:98: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:107: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:147: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:153: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:162: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:221: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:227: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:236: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:277: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:283: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/createMDFields.H:292: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
In file included from mdFoam.C:67:
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/calculateMDFields.H:13: error: ‘class Foam::molecule’ has no member named ‘U’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/calculateMDFields.H:17: error: ‘class Foam::molecule’ has no member named ‘mass’
In file included from mdFoam.C:69:
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/resetMDFields.H:5: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/resetMDFields.H:11: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/resetMDFields.H:17: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
/home/mehdi/OpenFOAM/OpenFOAM-1.6/src/lagrangian/molecularDynamics/molecule/lnInclude/resetMDFields.H:23: error: ‘class Foam::moleculeCloud’ has no member named ‘potential’
make: *** [Make/linuxGccDPOpt/mdFoam.o] Error 1
Can anyone help me with it ? ]]> OpenFOAM Running / Solving / CFD m.maneshi http://www.cfd-online.com/Forums/openfoam-solving/79612-error-recompiling-solver.html