[bob94]

Hi everybody!!

I recently started using openfoam for a project I'm working on.
In particular, I need a simulation of the heat exchange within a certain configuration. I'm trying using snappyHexMesh for creating the geometry and chtMultiRegionFoam as solver.

In my configuration I have both solids and fluids (air and alcohol).

When I only use solids I don't get errors, but when I go to insert fluids I almost always get errors when solving p_rgh (sometimes reaching the limit of iterations, other times instead of an error message).

To better understand the case:
- all the elements are at the same initial temperature of 300K and the fluids are always at atmospheric pressure
- in the constant/piastra folder I inserted an fvOptions file which operates a cooling of 100W
- to create the air zone in which the object is immersed, I inserted in the blockMesh file:

blocks
(
    hex (0 1 2 3 4 5 6 7) air (24 24 24) simpleGrading (1 1 1)
);

- for all temperature boundary conditions I used "compressible :: turbulentTemperatureCoupledBaffleMixed" and for all other parameters I used the same as the examples contained in the tutorials folder
- this is the error message

 

Region: air Courant Number mean: 0 max: 0
Region: alcool Courant Number mean: 0 max: 0
Region: piastra Diffusion Number mean: 0.24015812 max: 15.787614
Region: plexi Diffusion Number mean: 2.8440192e-05 max: 0.0032209747
Region: portaProv Diffusion Number mean: 0.31275907 max: 55.450193
Region: provette Diffusion Number mean: 0.001463558 max: 0.034645969
Region: strutSup Diffusion Number mean: 3.3476429e-05 max: 0.0087347803
deltaT = 0.00018034211
Region: air Courant Number mean: 0 max: 0
Region: alcool Courant Number mean: 0 max: 0
Region: piastra Diffusion Number mean: 0.043310623 max: 2.8471716
Region: plexi Diffusion Number mean: 5.1289642e-06 max: 0.00058087736
Region: portaProv Diffusion Number mean: 0.056403631 max: 10.000005
Region: provette Diffusion Number mean: 0.00026394114 max: 0.0062481271
Region: strutSup Diffusion Number mean: 6.0372098e-06 max: 0.0015752487
deltaT = 0.00018034211
Time = 0.000180342


Solving for fluid region air
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCGStab:  Solving for Ux, Initial residual = 1, Final residual = 1.9114871e-08, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 1, Final residual = 7.1856507e-06, No Iterations 1
DILUPBiCGStab:  Solving for Uz, Initial residual = 1, Final residual = 6.4711786e-09, No Iterations 1
DILUPBiCGStab:  Solving for h, Initial residual = 0.99995728, Final residual = 7.0966155e-09, No Iterations 1
Min/max T:300 300
GAMG:  Solving for p_rgh, Initial residual = 0.14514543, Final residual = 0.0061678691, No Iterations 3
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors (air): sum local = 1.2365165e-07, global = -9.7712567e-15, cumulative = -9.7712567e-15
GAMG:  Solving for p_rgh, Initial residual = 0.055844559, Final residual = 9.396246e-06, No Iterations 14
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors (air): sum local = 5.7911232e-09, global = -1.0337223e-14, cumulative = -2.010848e-14

Solving for fluid region alcool
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCGStab:  Solving for Ux, Initial residual = 1, Final residual = 1.4596229e-09, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 1, Final residual = 5.7710647e-09, No Iterations 1
DILUPBiCGStab:  Solving for Uz, Initial residual = 1, Final residual = 1.5093634e-09, No Iterations 1
DILUPBiCGStab:  Solving for h, Initial residual = 0.99985907, Final residual = 1.8031898e-11, No Iterations 1
Min/max T:300 300
GAMG:  Solving for p_rgh, Initial residual = 0.55243556, Final residual = 0.025787617, No Iterations 2
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors (alcool): sum local = 2.0166478e-06, global = -8.3913624e-17, cumulative = -8.3913624e-17
GAMG:  Solving for p_rgh, Initial residual = 0.89287755, Final residual = 7.5969844e-08, No Iterations 46
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors (alcool): sum local = 1.8039473e-12, global = -8.4504244e-17, cumulative = -1.6841787e-16

Solving for solid region piastra
DICPBiCGStab:  Solving for h, Initial residual = 1, Final residual = 6.0143068e-08, No Iterations 2
Min/max T:299.99993 300

Solving for solid region plexi
DICPBiCGStab:  Solving for h, Initial residual = 0.99975072, Final residual = 6.5126532e-07, No Iterations 1
Min/max T:299.99993 300

Solving for solid region portaProv
DICPBiCGStab:  Solving for h, Initial residual = 0.99999982, Final residual = 2.2015852e-07, No Iterations 2
Min/max T:299.99995 300

Solving for solid region provette
DICPBiCGStab:  Solving for h, Initial residual = 0.5391564, Final residual = 1.5222689e-09, No Iterations 1
Min/max T:300 300

Solving for solid region strutSup
DICPBiCGStab:  Solving for h, Initial residual = 0.54077457, Final residual = 2.0182476e-07, No Iterations 1
Min/max T:300 300
ExecutionTime = 11.32 s  ClockTime = 12 s

Region: air Courant Number mean: 1.9084062e-05 max: 0.00064475353
Region: alcool Courant Number mean: 1.7760967e-06 max: 9.0264841e-05
Region: piastra Diffusion Number mean: 0.043310623 max: 2.8471716
Region: plexi Diffusion Number mean: 5.1289642e-06 max: 0.00058087736
Region: portaProv Diffusion Number mean: 0.056403631 max: 10.000005
Region: provette Diffusion Number mean: 0.00026394114 max: 0.0062481271
Region: strutSup Diffusion Number mean: 6.0372098e-06 max: 0.0015752487
deltaT = 0.00018034211
Time = 0.000360684


Solving for fluid region air
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.33281853, Final residual = 1.1239572e-06, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.57572852, Final residual = 4.5837412e-06, No Iterations 1
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.33292171, Final residual = 1.7943607e-06, No Iterations 1
DILUPBiCGStab:  Solving for h, Initial residual = 0.99969992, Final residual = 9.9372367e-06, No Iterations 1
Min/max T:299.99998 300.00004
GAMG:  Solving for p_rgh, Initial residual = 0.16911283, Final residual = 0.0067219104, No Iterations 3
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors (air): sum local = 9.5467063e-08, global = 1.3920691e-14, cumulative = -6.1877887e-15
GAMG:  Solving for p_rgh, Initial residual = 0.054468682, Final residual = 9.8343803e-06, No Iterations 18
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors (air): sum local = 9.925107e-09, global = 1.9805379e-14, cumulative = 1.361759e-14

Solving for fluid region alcool
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.26438262, Final residual = 5.0872577e-10, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.45263081, Final residual = 1.3171118e-09, No Iterations 1
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.29110743, Final residual = 6.9864336e-10, No Iterations 1
DILUPBiCGStab:  Solving for h, Initial residual = 0.99999579, Final residual = 1.4432334e-11, No Iterations 1
Min/max T:299.99999 300.00003
GAMG:  Solving for p_rgh, Initial residual = 0.80060153, Final residual = 0.032809275, No Iterations 1
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors (alcool): sum local = 7.2218368e-08, global = -3.5140225e-17, cumulative = -2.0355809e-16
GAMG:  Solving for p_rgh, Initial residual = 0.18159713, Final residual = 7.5960323e-08, No Iterations 45
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors (alcool): sum local = 7.3563896e-14, global = -3.5132298e-17, cumulative = -2.3869039e-16

Solving for solid region piastra
DICPBiCGStab:  Solving for h, Initial residual = 0.97629277, Final residual = 9.90723e-07, No Iterations 2
Min/max T:299.99986 299.99998

Solving for solid region plexi
DICPBiCGStab:  Solving for h, Initial residual = 0.24353392, Final residual = 1.5918876e-07, No Iterations 1
Min/max T:299.99986 300

Solving for solid region portaProv
DICPBiCGStab:  Solving for h, Initial residual = 0.34170052, Final residual = 7.388575e-08, No Iterations 2
Min/max T:299.99991 300

Solving for solid region provette
DICPBiCGStab:  Solving for h, Initial residual = 0.99992906, Final residual = 8.4265129e-10, No Iterations 1
Min/max T:299.99999 300.00002

Solving for solid region strutSup
DICPBiCGStab:  Solving for h, Initial residual = 0.97894798, Final residual = 2.9735002e-07, No Iterations 1
Min/max T:300 300
ExecutionTime = 13.76 s  ClockTime = 15 s

Region: air Courant Number mean: 2.9965953e-05 max: 0.0006902855
Region: alcool Courant Number mean: 1.2285228e-06 max: 4.9915036e-05
Region: piastra Diffusion Number mean: 0.043310623 max: 2.8471716
Region: plexi Diffusion Number mean: 5.1289642e-06 max: 0.00058087736
Region: portaProv Diffusion Number mean: 0.056403631 max: 10.000005
Region: provette Diffusion Number mean: 0.00026394114 max: 0.0062481271
Region: strutSup Diffusion Number mean: 6.0372098e-06 max: 0.0015752487
deltaT = 0.00018034211
Time = 0.000541026


Solving for fluid region air
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.19702503, Final residual = 1.5808326e-07, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.23696084, Final residual = 1.7058751e-06, No Iterations 1
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.2371358, Final residual = 8.6132764e-07, No Iterations 1
DILUPBiCGStab:  Solving for h, Initial residual = 0.98522741, Final residual = 5.5073739e-06, No Iterations 1
Min/max T:299.99983 300.0002
GAMG:  Solving for p_rgh, Initial residual = 0.33982312, Final residual = 0.019533347, No Iterations 2
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors (air): sum local = 1.6954736e-07, global = -1.2716672e-14, cumulative = 9.0091772e-16
GAMG:  Solving for p_rgh, Initial residual = 0.10996116, Final residual = 8.5437486e-06, No Iterations 22
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors (air): sum local = 1.1619869e-08, global = 6.9900636e-16, cumulative = 1.5999241e-15

Solving for fluid region alcool
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.078586205, Final residual = 3.6182856e-10, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.15353674, Final residual = 9.7023274e-10, No Iterations 1
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.28874942, Final residual = 6.8418329e-10, No Iterations 1
DILUPBiCGStab:  Solving for h, Initial residual = 0.75356235, Final residual = 1.8520723e-09, No Iterations 1
Min/max T:299.99971 300.00003
GAMG:  Solving for p_rgh, Initial residual = 0.17236852, Final residual = 0.011704416, No Iterations 1
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors (alcool): sum local = 1.1639358e-08, global = -8.441821e-17, cumulative = -3.231086e-16
[3] #0  Foam::error::printStack(Foam::Ostream&) at ??:?
[3] #1  Foam::sigFpe::sigHandler(int) at ??:?
[3] #2  ? in /lib64/libc.so.6
[3] #3  Foam::scalarProduct<double, double>::type Foam::sumProd<double>(Foam::UList<double> const&, Foam::UList<double> const&) at ??:?
[3] #4  Foam::PCG::scalarSolve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
[3] #5  Foam::GAMGSolver::solveCoarsestLevel(Foam::Field<double>&, Foam::Field<double> const&) const at ??:?
[3] #6  Foam::GAMGSolver::Vcycle(Foam::PtrList<Foam::lduMatrix::smoother> const&, Foam::Field<double>&, Foam::Field<double> const&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::PtrList<Foam::Field<double> >&, Foam::PtrList<Foam::Field<double> >&, unsigned char) const at ??:?
[3] #7  Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
[3] #8  Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&) at ??:?
[3] #9  Foam::fvMatrix<double>::solveSegregatedOrCoupled(Foam::dictionary const&) at ??:?
[3] #10  Foam::fvMesh::solve(Foam::fvMatrix<double>&, Foam::dictionary const&) const at ??:?
[3] #11  ? at ??:?
[3] #12  __libc_start_main in /lib64/libc.so.6
[3] #13  ? at ??:?
[e8c14275c37d:01576] *** Process received signal ***
[e8c14275c37d:01576] Signal: Floating point exception (8)
[e8c14275c37d:01576] Signal code:  (-6)
[e8c14275c37d:01576] Failing at address: 0x628
[e8c14275c37d:01576] [ 0] /lib64/libc.so.6(+0x35270)[0x7f8bbf62e270]
[e8c14275c37d:01576] [ 1] /lib64/libc.so.6(gsignal+0x37)[0x7f8bbf62e1f7]
[e8c14275c37d:01576] [ 2] /lib64/libc.so.6(+0x35270)[0x7f8bbf62e270]
[e8c14275c37d:01576] [ 3] /opt/OpenFOAM/OpenFOAM-v1912/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZN4Foam7sumProdIdEENS_13scalarProductIT_S2_E4typeERKNS_5UListIS2_EES8_+0x25)[0x7f8bc0b17cc5]
[e8c14275c37d:01576] [ 4] /opt/OpenFOAM/OpenFOAM-v1912/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam3PCG11scalarSolveERNS_5FieldIdEERKS2_h+0x9c5)[0x7f8bc096a675]
[e8c14275c37d:01576] [ 5] /opt/OpenFOAM/OpenFOAM-v1912/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam10GAMGSolver18solveCoarsestLevelERNS_5FieldIdEERKS2_+0x91)[0x7f8bc0988511]
[e8c14275c37d:01576] [ 6] /opt/OpenFOAM/OpenFOAM-v1912/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam10GAMGSolver6VcycleERKNS_7PtrListINS_9lduMatrix8smootherEEERNS_5FieldIdEERKS8_S9_S9_S9_S9_S9_RNS1_IS8_EESD_h+0x71e)[0x7f8bc098936e]
[e8c14275c37d:01576] [ 7] /opt/OpenFOAM/OpenFOAM-v1912/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam10GAMGSolver5solveERNS_5FieldIdEERKS2_h+0x5ea)[0x7f8bc098bb7a]
[e8c14275c37d:01576] [ 8] /opt/OpenFOAM/OpenFOAM-v1912/platforms/linux64GccDPInt32Opt/lib/libfiniteVolume.so(_ZN4Foam8fvMatrixIdE15solveSegregatedERKNS_10dictionaryE+0x11f)[0x7f8bc76d620f]
[e8c14275c37d:01576] [ 9] /opt/OpenFOAM/OpenFOAM-v1912/platforms/linux64GccDPInt32Opt/lib/libfiniteVolume.so(_ZN4Foam8fvMatrixIdE24solveSegregatedOrCoupledERKNS_10dictionaryE+0x27f)[0x7f8bc702b08f]
[e8c14275c37d:01576] [10] /opt/OpenFOAM/OpenFOAM-v1912/platforms/linux64GccDPInt32Opt/lib/libfiniteVolume.so(_ZNK4Foam6fvMesh5solveERNS_8fvMatrixIdEERKNS_10dictionaryE+0xf)[0x7f8bc6fed45f]
[e8c14275c37d:01576] [11] chtMultiRegionFoam[0x43a550]
[e8c14275c37d:01576] [12] /lib64/libc.so.6(__libc_start_main+0xf5)[0x7f8bbf61ac05]
[e8c14275c37d:01576] [13] chtMultiRegionFoam[0x440fa6]
[e8c14275c37d:01576] *** End of error message ***
--------------------------------------------------------------------------
mpirun noticed that process rank 3 with PID 1576 on node e8c14275c37d exited on signal 8 (Floating point exception).

- in many tests that I have done sometimes it happened that trying to solve in parallel instead of on a single processor I did not get errors

- I created the stl files through AutoCad and then imported / modified and exported them through blender

- I also tried to isolate the mesh with the subSet command (the test I did with solids only) but when I insert more fluids I get this error

My questions are therefore:
- am I using the right solver?
- what are the initial values ​​of p_rgh (for liquid and for gas), the boundary conditions and best solver in fvSolution?
- why sometimes I don't get errors if I run in parallel
P.S.
even if I finish the simulation very often I don't get what I expect (heat not transmitted inside a solid, strange pressure values ​​or temperature values ​​higher than 300K even if I only have cooling)