[Swift]

Dear Foamers,

I'm using OF1806 to model the rotation of two rotors offset from each other, each with two blades. This is a multiphase problem, so I am using overInterDyMFoam.

I have been running on a single processor, but on changing to parallel processing I receive the following error on the first iteration step:

Execution time for mesh.update() = 0.79 s
smoothSolver:  Solving for alpha.water, Initial residual = 1.353549218e-09, Final residual = 1.353549218e-09, No Iterations 0
Phase-1 volume fraction = 0.4181040843  Min(alpha.water) = 0  Max(alpha.water) = 1
MULES: Correcting alpha.water
MULES: Correcting alpha.water
MULES: Correcting alpha.water
Phase-1 volume fraction = 0.4181104467  Min(alpha.water) = 0  Max(alpha.water) = 1
smoothSolver:  Solving for alpha.water, Initial residual = 2.322414915e-16, Final residual = 2.322414915e-16, No Iterations 0
Phase-1 volume fraction = 0.4181104467  Min(alpha.water) = 0  Max(alpha.water) = 1
MULES: Correcting alpha.water
MULES: Correcting alpha.water
MULES: Correcting alpha.water
Phase-1 volume fraction = 0.4181104467  Min(alpha.water) = 0  Max(alpha.water) = 1
DILUPBiCG:  Solving for Ux, Initial residual = 1, Final residual = 2.83028911e-10, No Iterations 2
DILUPBiCG:  Solving for Uz, Initial residual = 1, Final residual = 4.743562107e-11, No Iterations 2
DILUPBiCG:  Solving for p_rgh, Initial residual = 0.9995489713, Final residual = 0.1032830896, No Iterations 1000
DILUPBiCG:  Solving for p_rgh, Initial residual = 0.05135346298, Final residual = 54033200.29, No Iterations 1000
DILUPBiCG:  Solving for p_rgh, Initial residual = 0.9945517149, Final residual = 0.2754961416, No Iterations 1000
DILUPBiCG:  Solving for p_rgh:  solution singularity
time step continuity errors : sum local = 1.637118569e+23, global = -1.875729674e+21, cumulative = -1.875729674e+21
DILUPBiCG:  Solving for p_rgh, Initial residual = 1, Final residual = 627.3066397, No Iterations 1000
DILUPBiCG:  Solving for p_rgh, Initial residual = 0.7921979107, Final residual = 0.1789164504, No Iterations 1000
DILUPBiCG:  Solving for p_rgh, Initial residual = 0.4782676038, Final residual = 3.608746382, No Iterations 1000
DILUPBiCG:  Solving for p_rgh, Initial residual = 0.8500953436, Final residual = 0.08637729416, No Iterations 1000
time step continuity errors : sum local = 9.608309622e+46, global = -2.32551894e+45, cumulative = -2.32551894e+45
DILUPBiCG:  Solving for p_rgh, Initial residual = 1, Final residual = 149.1396146, No Iterations 1000
DILUPBiCG:  Solving for p_rgh, Initial residual = 0.9226201229, Final residual = 2.655674273e+10, No Iterations 1000
DILUPBiCG:  Solving for p_rgh, Initial residual = 0.9318445964, Final residual = 1.991960637, No Iterations 1000
DILUPBiCG:  Solving for p_rgh, Initial residual = 0.960292077, Final residual = 23587.71697, No Iterations 1000
time step continuity errors : sum local = 1.426870104e+110, global = -1.815010396e+108, cumulative = -1.815010396e+108
[1] #0  Foam::error::printStack(Foam::Ostream&)[0] #0  Foam::error::printStack(Foam::Ostream&) at ??:?
 at ??:?
[0] #1  Foam::sigFpe::sigHandler(int)[1] #1  Foam::sigFpe::sigHandler(int) at ??:?
[1] #2  ? at ??:?
[0] #2  ? in /lib64/libc.so.6
 in /lib64/libc.so.6
[1] #3  double Foam::sumProd<double>(Foam::UList<double> const&, Foam::UList<double> const&)[0] #3  double Foam::sumProd<double>(Foam::UList<double> const&, Foam::UList<double> const&) at ??:?
 at ??:?
[1] #4  Foam::PBiCG::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const[0] #4  Foam::PBiCG::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
 at ??:?
[1] #5  Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&)[0] #5  Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&) at ??:?
 at ??:?
[1] #6  Foam::fvMatrix<double>::solveSegregatedOrCoupled(Foam::dictionary const&)[0] #6  Foam::fvMatrix<double>::solveSegregatedOrCoupled(Foam::dictionary const&) at ??:?
 at ??:?
[0] #7  [1] #7  Foam::fvMesh::solve(Foam::fvMatrix<double>&, Foam::dictionary const&) constFoam::fvMesh::solve(Foam::fvMatrix<double>&, Foam::dictionary const&) const at ??:?
[1] #8  Foam::SolverPerformance<double> Foam::dynamicOversetFvMesh::solve<double>(Foam::fvMatrix<double>&, Foam::dictionary const&) const at ??:?
[0] #8  Foam::SolverPerformance<double> Foam::dynamicOversetFvMesh::solve<double>(Foam::fvMatrix<double>&, Foam::dictionary const&) const at ??:?
[1] #9  Foam::dynamicOversetFvMesh::solve(Foam::fvMatrix<double>&, Foam::dictionary const&) const at ??:?
[0] #9  Foam::dynamicOversetFvMesh::solve(Foam::fvMatrix<double>&, Foam::dictionary const&) const at ??:?
[1] #10   at ??:?
[0] #10  ?? at ??:?
[0] #11   at ??:?
[1] #11  __libc_start_main__libc_start_main in /lib64/libc.so.6
[1] # in /lib64/libc.so.6
12  [0] #12  ?? at ??:?
[83743d5aaf09:01547] *** Process received signal ***
[83743d5aaf09:01547] Signal: Floating point exception (8)
[83743d5aaf09:01547] Signal code:  (-6)
[83743d5aaf09:01547] Failing at address: 0x3e80000060b
[83743d5aaf09:01547] [ 0]  at ??:?
[83743d5aaf09:01546] *** Process received signal ***
/lib64/libc.so.6(+0x35270)[0x7f2d42a16270]
[83743d5aaf09:01547] [ 1] [83743d5aaf09:01546] Signal: Floating point exception (8)
[83743d5aaf09:01546] Signal code:  (-6)
[83743d5aaf09:01546] Failing at address: 0x3e80000060a
/lib64/libc.so.6(gsignal+0x37)[0x7f2d42a161f7]
[83743d5aaf09:01547] [ 2] /lib64/libc.so.6(+0x35270)[0x7f2d42a16270]
[83743d5aaf09:01547] [ 3] [83743d5aaf09:01546] [ 0] /lib64/libc.so.6(+0x35270)[0x7ffa10f9a270]
[83743d5aaf09:01546] [ 1] /lib64/libc.so.6(gsignal+0x37)[0x7ffa10f9a1f7]
[83743d5aaf09:01546] [ 2] /lib64/libc.so.6(+0x35270)[0x7ffa10f9a270]
[83743d5aaf09:01546] [ 3] /opt/OpenFOAM/OpenFOAM-v1806/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZN4Foam7sumProdIdEEdRKNS_5UListIT_EES5_+0x30)[0x7f2d43e48200]
[83743d5aaf09:01547] [ 4] /opt/OpenFOAM/OpenFOAM-v1806/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZN4Foam7sumProdIdEEdRKNS_5UListIT_EES5_+0x25)[0x7ffa123cc1f5]
[83743d5aaf09:01546] [ 4] /opt/OpenFOAM/OpenFOAM-v1806/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam5PBiCG5solveERNS_5FieldIdEERKS2_h+0xa3e)[0x7f2d43c9950e]
[83743d5aaf09:01547] [ 5] /opt/OpenFOAM/OpenFOAM-v1806/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam5PBiCG5solveERNS_5FieldIdEERKS2_h+0xa3e)[0x7ffa1221d50e]
[83743d5aaf09:01546] [ 5] /opt/OpenFOAM/OpenFOAM-v1806/platforms/linux64GccDPInt32Opt/lib/libfiniteVolume.so(_ZN4Foam8fvMatrixIdE15solveSegregatedERKNS_10dictionaryE+0x11e)[0x7f2d46dddade]
[83743d5aaf09:01547] [ 6] /opt/OpenFOAM/OpenFOAM-v1806/platforms/linux64GccDPInt32Opt/lib/libfiniteVolume.so(_ZN4Foam8fvMatrixIdE15solveSegregatedERKNS_10dictionaryE+0x11e)[0x7ffa15361ade]
[83743d5aaf09:01546] [ 6] /opt/OpenFOAM/OpenFOAM-v1806/platforms/linux64GccDPInt32Opt/lib/libfiniteVolume.so(_ZN4Foam8fvMatrixIdE24solveSegregatedOrCoupledERKNS_10dictionaryE+0x285)[0x7f2d4691f745]
[83743d5aaf09:01547] [ 7] /opt/OpenFOAM/OpenFOAM-v1806/platforms/linux64GccDPInt32Opt/lib/libfiniteVolume.so(_ZNK4Foam6fvMesh5solveERNS_8fvMatrixIdEERKNS_10dictionaryE+0xf)[0x7f2d468e655f]
[83743d5aaf09:01547] [ 8] /opt/OpenFOAM/OpenFOAM-v1806/platforms/linux64GccDPInt32Opt/lib/libfiniteVolume.so(_ZN4Foam8fvMatrixIdE24solveSegregatedOrCoupledERKNS_10dictionaryE+0x285)[0x7ffa14ea3745]
[83743d5aaf09:01546] [ 7] /opt/OpenFOAM/OpenFOAM-v1806/platforms/linux64GccDPInt32Opt/lib/liboverset.so(_ZNK4Foam20dynamicOversetFvMesh5solveIdEENS_17SolverPerformanceIT_EERNS_8fvMatrixIS3_EERKNS_10dictionaryE+0x217)[0x7f2d4521ea37]
[83743d5aaf09:01547] [ 9] /opt/OpenFOAM/OpenFOAM-v1806/platforms/linux64GccDPInt32Opt/lib/liboverset.so(_ZNK4Foam20dynamicOversetFvMesh5solveERNS_8fvMatrixIdEERKNS_10dictionaryE+0x9)[0x7f2d4521eda9]
[83743d5aaf09:01547] [10] overInterDyMFoam[0x44793f]
[83743d5aaf09:01547] [11] /lib64/libc.so.6(__libc_start_main+0xf5)[0x7f2d42a02c05]
[83743d5aaf09:01547] [12] overInterDyMFoam[0x450ea2]
[83743d5aaf09:01547] *** End of error message ***
/opt/OpenFOAM/OpenFOAM-v1806/platforms/linux64GccDPInt32Opt/lib/libfiniteVolume.so(_ZNK4Foam6fvMesh5solveERNS_8fvMatrixIdEERKNS_10dictionaryE+0xf)[0x7ffa14e6a55f]
[83743d5aaf09:01546] [ 8] /opt/OpenFOAM/OpenFOAM-v1806/platforms/linux64GccDPInt32Opt/lib/liboverset.so(_ZNK4Foam20dynamicOversetFvMesh5solveIdEENS_17SolverPerformanceIT_EERNS_8fvMatrixIS3_EERKNS_10dictionaryE+0x217)[0x7ffa137a2a37]
[83743d5aaf09:01546] [ 9] /opt/OpenFOAM/OpenFOAM-v1806/platforms/linux64GccDPInt32Opt/lib/liboverset.so(_ZNK4Foam20dynamicOversetFvMesh5solveERNS_8fvMatrixIdEERKNS_10dictionaryE+0x9)[0x7ffa137a2da9]
[83743d5aaf09:01546] [10] overInterDyMFoam[0x44793f]
[83743d5aaf09:01546] [11] /lib64/libc.so.6(__libc_start_main+0xf5)[0x7ffa10f86c05]
[83743d5aaf09:01546] [12] overInterDyMFoam[0x450ea2]
[83743d5aaf09:01546] *** End of error message ***

I have noticed that p_rgh gives the error:

Solving for p_rgh:  solution singularity

The same error came up in

https://www.cfd-online.com/Forums/openfoam-solving/59814-solution-singularity.html

The suggestion was to check BC, viscosity and relaxation factors. My problem is that this only appears when running in parallel, which makes me think that this shouldn't be the problem. Needless to say, I did check viscosity and changed the relaxation factors from 1 to 0.5.

For my BCs, as I said this works on a single core. I had a pressureInletOutletBC on the top wall to simulate an open to atmosphere condition. This was based off the tutorials. I also tried changing this from pressureInletOutlet to a wall. I have no other inlets or outlets into the domain.

While I say it runs one a single core, I haven't run it that long and it may still crash.

I've attached my case, but I had to remove the mesh because it was too big.

Does anyone have any more ideas on how to fix this or how to try and diagnose this further?

Thanks,
Thomas

[Himanshu_B]

Try,


massFluxInterpolation false;



in PIMPLE section