[BenJ]

Hi everyone!

I am trying to use rhoSimpleFoam with hPsiThermo<pureMixture<SutherlandTransport<specieT hermo<hConstThermo<perfectGas.

I have already run a case with an hexaedral mesh created with bockMesh, but with a new mesh built with thetraedrical cells (from fluent), it does not run with the same boundary conditions.

Can anyone help me?

Thanks
Ben

[massive_turbulence]

Originally Posted by BenJ

Hi everyone!

I am trying to use rhoSimpleFoam with hPsiThermo<pureMixture<SutherlandTransport<specieT hermo<hConstThermo<perfectGas.

I have already run a case with an hexaedral mesh created with bockMesh, but with a new mesh built with thetraedrical cells (from fluent), it does not run with the same boundary conditions.

Can anyone help me?

Thanks
Ben

Have you tried this page? http://www.openfoam.org/features/mesh-conversion.php

[BenJ]

Hi massive_turbulence

Thank you for your answer.

Yes, I did convert the mesh with the FluentToFoam utility.

I should be more precise, my mistake. When I try to run the case with exactly the same boundary conditions, system file and constant properties (thermodynamics, turbulence model etc...), when I only change the mesh, the first time iteration runs for velocity components, but crashes after calculating the enthalpy h (and I tried it with different solvers).

Here is the message I get :

#0 Foam::error:rintStack(Foam::Ostream&) in "/software/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#1 Foam::sigFpe::sigHandler(int) in "/software/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#2 in "/lib64/libc.so.6"
#3 Foam::hPsiThermo<Foam:ureMixture<Foam::sutherlan dTransport<Foam::specieThermo<Foam::hConstThermo<F oam:erfectGas> > > > >::calculate() in "/software/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libbasicThermophysicalModels.so"
#4 Foam::hPsiThermo<Foam:ureMixture<Foam::sutherlan dTransport<Foam::specieThermo<Foam::hConstThermo<F oam:erfectGas> > > > >::correct() in "/software/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libbasicThermophysicalModels.so"
#5
in "/software/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/bin/rhoSimpleFoam"
#6 __libc_start_main in "/lib64/libc.so.6"
#7
at /home/abuild/rpmbuild/BUILD/glibc-2.14.1/csu/../sysdeps/x86_64/elf/start.S:116
Gleitkomma-Ausnahme

Thanks a lot for your help!
BenJ

[alexeym]

Hi,

can you show:

1. Output of checkMesh utility
2. Your fvSchemes, fvSolution, and controlDict

[BenJ]

Hi Alexeym,

Thank you for your interest!

Here is the result of checkMesh:

Create time
Create polyMesh for time = 0
Time = 0
Mesh stats
points: 158315
faces: 1675145
internal faces: 1603215
cells: 819590
boundary patches: 12
point zones: 0
face zones: 0
cell zones: 0
Overall number of cells of each type:
hexahedra: 0
prisms: 0
wedges: 0
pyramids: 0
tet wedges: 0
tetrahedra: 819590
polyhedra: 0

Checking topology...
****Problem with boundary patch 0 named inlet of type patch. The patch should start on face no 1603215 and the patch specifies 1604156.
Possibly consecutive patches have this same problem. Suppressing future warnings.
***Boundary definition is in error.
Cell to face addressing OK.
Point usage OK.
Upper triangular ordering OK.
Face vertices OK.
Number of regions: 1 (OK).
Checking patch topology for multiply connected surfaces ...
Patch Faces Points Surface topology
inlet 923 525 ok (non-closed singly connected)
outlet 941 534 ok (non-closed singly connected)
ground 47959 24352 ok (non-closed singly connected)
car 12430 6280 ok (non-closed singly connected)
out01 205 129 ok (non-closed singly connected)
in01 65 44 ok (non-closed singly connected)
in02 67 45 ok (non-closed singly connected)
in03 63 43 ok (non-closed singly connected)
in04 66 45 ok (non-closed singly connected)
top 3380 1786 ok (non-closed singly connected)
left 2651 1521 ok (non-closed singly connected)
right 3180 1785 ok (non-closed singly connected)

Checking geometry...
Overall domain bounding box (0 0 0) (220 30 60)
Mesh (non-empty, non-wedge) directions (1 1 1)
Mesh (non-empty) directions (1 1 1)
Boundary openness (-2.66364e-17 2.47972e-15 1.16455e-16) OK.
Max cell openness = 3.00333e-16 OK.
Max aspect ratio = 5.58785 OK.
Minumum face area = 0.00159453. Maximum face area = 8.97168. Face area magnitudes OK.
Min volume = 3.60741e-05. Max volume = 6.9714. Total volume = 394606. Cell volumes OK.
Mesh non-orthogonality Max: 59.3015 average: 13.9372
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 0.650403 OK.
Coupled point location match (average 0) OK.

Mesh OK.

End

Here is controlDict:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.1.1 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
application rhosimpleFoam;
startFrom latestTime;
startTime 0;
stopAt endTime;
endTime 4;
deltaT 0.002;
writeControl timeStep;
writeInterval 20;
purgeWrite 0;
writeFormat ascii;
writePrecision 6;
writeCompression off;
timeFormat general;
timePrecision 6;
runTimeModifiable true;
// ************************************************** *********************** //

fvSchemes:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.1.1 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
ddtSchemes
{
default steadyState;
}
gradSchemes
{
default Gauss linear;
}
divSchemes
{
default none;

div(phi,U) Gauss upwind;
div((muEff*dev2(T(grad(U))))) Gauss linear;
div(phi,h) Gauss upwind;
div(phi,omega) Gauss upwind;
div(phi,k) Gauss upwind;
div(phi,K) Gauss upwind;
}
laplacianSchemes
{
default Gauss linear corrected;

}
interpolationSchemes
{
default linear;
}
snGradSchemes
{
default corrected;
}
fluxRequired
{
default no;
p;
}
// ************************************************** *********************** //

fvSolution:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.1.1 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
solvers
{
p
{
solver GAMG;
tolerance 1e-7;
relTol 0.1;
smoother GaussSeidel;
nPreSweeps 0;
nPostSweeps 2;
cacheAgglomeration off;
agglomerator faceAreaPair;
nCellsInCoarsestLevel 10;
mergeLevels 1;

}
U
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-8;
relTol 0.1;
nSweeps 1;
}
k
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-8;
relTol 0.1;
nSweeps 1;
}
omega
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-8;
relTol 0.1;
nSweeps 1;
}

h
{
solver PBiCG;
preconditioner DILU;
tolerance 1e-06;
relTol 0.1;
}
}
SIMPLE
{
nNonOrthogonalCorrectors 0;
rhoMin rhoMin [ 1 -3 0 0 0 ] 0.5;
rhoMax rhoMax [ 1 -3 0 0 0 ] 1.5;
}
potentialFlow
{
nNonOrthogonalCorrectors 10;
}
relaxationFactors
{
fields
{
p 0.3;
rho 0.05;
}
equations
{
U 0.7;
k 0.7;
omega 0.7;
h 0.5;
}
}
cache
{
grad(U);
}
// ************************************************** *********************** //

Thank you for your help!

[BenJ]

Hi again,

It seems that the problem does not come from the mesh, but from my settings. I have exactly the same issue with rhoSimplecFoam after 12 iterations and an hexahedral mesh...

So I think my fvSchemes or fvSolution are not adapted for these compressible solvers... what should I set?

BenJ

[alexeym]

Hi,

my suggestions will be rather general:

1. Have you tried to run simulation with smaller time step?

2. Try cellMDLimited (or just cellLimited) scheme for gradients. I.e. instead

default Gauss linear;

try

default cellMDLimited Gauss linear 1.0;

Since it seems you've not reached the stage of solving pressure equation, you can start with just these modifications of the settings.

[BenJ]

Hi Alexeym !

Thanks for these advices!

I tried to replace the scheme for gradient. In fact, it does run for a few iterations (42), but it crashes and gives me the same floating point exception.

Before you answered, I also tried to replace the scheme for divergence. I tried Gauss linear corrected. But, again, after 47 iterations, it crashes and returns the same floating point exception...

So, I guess I should try another scheme... But I don´t really know where I could have good informations about this subject. The OpenFOAM user´s Guide is a bit light about it.

About the time step, I thought it has no influence for steady-state solver?

Thanks again!
BenJ

[alexeym]

Hi,

well, as I don't know the actual problem you're trying to solve I'll try to give another set of rather general suggestions:

1. Change smoothSolvers to PBiCG for U, k, omega.
2. Change GAMG to PCG for pressure. Or at least set nCellsInCoarsestLevel to square root of the number of cells in your mesh.
3. Reduce relaxation factors even more (i.e. increase relaxation).
4. Add even more viscosity changing cellLimited to faceLimited.

I really don't know where to learn about discretisation schemes except going though sources (you can find certain hints in http://www.dicat.unige.it/guerrero/o...sandtricks.pdf).

You're right about time step, didn't pay attention to Simple in solver name.

[BenJ]

Hi!

Thanks for your answer. I did try to change the fvSchemes and fvSolution files. It worked well, but the residuals were oscillating, tending to be amplified.
I will try to use the results of this simulation as initial conditions for a simulation with other solvers.

Thanks again
BenJ

[BenJ]

Hi!

Running other solver (rhoCentralFoam), with the fvSchemes and Solution above, I get the same error message.
And this is about thermophysicalProperties... I don't know where I can change something to male this work.

Does anyone have an idea?

BenJ

[BenJ]

Hi!

So, with your advices Alexeym, it ran, but crashed after 200 iterations...

If it can help, here are the last terminal out:

Time = 0.55
DILUPBiCG: Solving for Ux, Initial residual = 0.0566853, Final residual = 2.29868e-05, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.0649065, Final residual = 3.16794e-05, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.0570885, Final residual = 2.77855e-05, No Iterations 1
DILUPBiCG: Solving for h, Initial residual = 0.0214908, Final residual = 5.69351e-06, No Iterations 1
DICPCG: Solving for p, Initial residual = 0.677055, Final residual = 0.0660593, No Iterations 35
time step continuity errors : sum local = 0.000308196, global = -3.82253e-05, cumulative = -0.000191121
rho max/min : 1.48201 0.841161
DILUPBiCG: Solving for omega, Initial residual = 0.00462973, Final residual = 1.49717e-06, No Iterations 1
bounding omega, min: -43.849 max: 5271.65 average: 8.24766
DILUPBiCG: Solving for k, Initial residual = 0.00379471, Final residual = 3.17851e-06, No Iterations 1
bounding k, min: -4.47456 max: 567.125 average: 0.256878
ExecutionTime = 486.12 s ClockTime = 543 s
Time = 0.552
DILUPBiCG: Solving for Ux, Initial residual = 0.0563291, Final residual = 2.28632e-05, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.0634064, Final residual = 3.09718e-05, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.056279, Final residual = 2.73982e-05, No Iterations 1
DILUPBiCG: Solving for h, Initial residual = 0.0213536, Final residual = 5.86027e-06, No Iterations 1
#0 Foam::error:rintStack(Foam::Ostream&) in "/software/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#1 Foam::sigFpe::sigHandler(int) in "/software/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#2 in "/lib64/libc.so.6"
#3 Foam::hPsiThermo<Foam:ureMixture<Foam::sutherlan dTransport<Foam::specieThermo<Foam::hConstThermo<F oam:erfectGas> > > > >::calculate() in "/software/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libbasicThermophysicalModels.so"
#4 Foam::hPsiThermo<Foam:ureMixture<Foam::sutherlan dTransport<Foam::specieThermo<Foam::hConstThermo<F oam:erfectGas> > > > >::correct() in "/software/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libbasicThermophysicalModels.so"
#5
in "/software/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/bin/rhoSimpleFoam"
#6 __libc_start_main in "/lib64/libc.so.6"
#7
at /home/abuild/rpmbuild/BUILD/glibc-2.14.1/csu/../sysdeps/x86_64/elf/start.S:116
Floating Point Exception

I am trying to change the mesh. Import from fluent could be the cause of bad calculation?
BenJ

[dahicocuk]

Hi Alexeym,

I want to use nanofluids for laminar pipe flow simulations.The thermophysical properties of nanofluids are as a functions of temperature thus I need to add temperature equation in rhoSimpleFoam.Could you please let me know how I can make it?

Thank you.

Best Regards.

[cfdjunkie]

Hello BenJ,

Have you found the solution to the sigFPE error for the thermophysical model?

I am running a 2D unsteady, compressible flow over a backward facing step and I get the exact same error.
I tried all the suggestion by alexyem and it just increases the number of iterations after which it crashes. Just like you had.
Also the residuals oscillate and tend to diverge.

I would really appreciate any help I can get on this matter. From anybody!

I can post more details if anyone requires it.

Regards,
Dhaval