[Ruli]

Dear Foamers,
once again I have a new question.

I am calculating a wind turbine rotor blade with RANS k-omega-SST and MRF approach using the simple solver (OF 2.2.2). My mesh is a 120° slice of the whole rotor with one blade in it and cyclic side patches. I calculated parallelized. So much on the case.

Currently I am testing severeal geometrical pitch angles and angular velocities of the rotor blade to find optimum operational conditions. Everything worked fine for the tested parameters, the simulation did converge (more or less, sometimes it crashed after ~2000 iterations).

Now I varied the pitch angle in the opposite direction as before and I get an unknown error after 10 to 100 steps (depending on snappy and solver settings), which I do not understand:

julian@julian-Pc:~/OpenFOAM/julian-2.2.2/run/MRF_20140131$ [1] #0  Foam::error::printStack(Foam::Ostream&) at ??:?
[1] #1  Foam::sigFpe::sigHandler(int) at ??:?
[1] #2   in "/lib/x86_64-linux-gnu/libc.so.6"
[1] #3  Foam::GAMGSolver::scale(Foam::Field<double>&, Foam::Field<double>&, Foam::lduMatrix const&, Foam::FieldField<Foam::Field, double> const&, Foam::UPtrList<Foam::lduInterfaceField const> const&, Foam::Field<double> const&, unsigned char) const at ??:?
[1] #4  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::PtrList<Foam::Field<double> >&, Foam::PtrList<Foam::Field<double> >&, unsigned char) const at ??:?
[1] #5  Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
[1] #6  Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&) at ??:?
[1] #7  Foam::fvMatrix<double>::solve(Foam::dictionary const&) at ??:?
[1] #8  
[1]  at ??:?
[1] #9  
[1]  at ??:?
[1] #10  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
[1] #11  
[1]  at ??:?
[julian-Pc:24282] *** Process received signal ***
[julian-Pc:24282] Signal: Floating point exception (8)
[julian-Pc:24282] Signal code:  (-6)
[julian-Pc:24282] Failing at address: 0x3e800005eda
[julian-Pc:24282] [ 0] /lib/x86_64-linux-gnu/libc.so.6(+0x36ff0) [0x7fa66e448ff0]
[julian-Pc:24282] [ 1] /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x37) [0x7fa66e448f77]
[julian-Pc:24282] [ 2] /lib/x86_64-linux-gnu/libc.so.6(+0x36ff0) [0x7fa66e448ff0]
[julian-Pc:24282] [ 3] /opt/openfoam222/platforms/linux64GccDPOpt/lib/libOpenFOAM.so(_ZNK4Foam10GAMGSolver5scaleERNS_5FieldIdEES3_RKNS_9lduMatrixERKNS_10FieldFieldIS1_dEERKNS_8UPtrListIKNS_17lduInterfaceFieldEEERKS2_h+0x239) [0x7fa66f566949]
[julian-Pc:24282] [ 4] /opt/openfoam222/platforms/linux64GccDPOpt/lib/libOpenFOAM.so(_ZNK4Foam10GAMGSolver6VcycleERKNS_7PtrListINS_9lduMatrix8smootherEEERNS_5FieldIdEERKS8_S9_S9_S9_RNS1_IS8_EESD_h+0xd5d) [0x7fa66f56923d]
[julian-Pc:24282] [ 5] /opt/openfoam222/platforms/linux64GccDPOpt/lib/libOpenFOAM.so(_ZNK4Foam10GAMGSolver5solveERNS_5FieldIdEERKS2_h+0x5c2) [0x7fa66f56aca2]
[julian-Pc:24282] [ 6] /opt/openfoam222/platforms/linux64GccDPOpt/lib/libfiniteVolume.so(_ZN4Foam8fvMatrixIdE15solveSegregatedERKNS_10dictionaryE+0x12f) [0x7fa6710f9eef]
[julian-Pc:24282] [ 7] simpleFoam(_ZN4Foam8fvMatrixIdE5solveERKNS_10dictionaryE+0x119) [0x445119]
[julian-Pc:24282] [ 8] simpleFoam() [0x4453fd]
[julian-Pc:24282] [ 9] simpleFoam() [0x41abdb]
[julian-Pc:24282] [10] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5) [0x7fa66e433de5]
[julian-Pc:24282] [11] simpleFoam() [0x41b7be]
[julian-Pc:24282] *** End of error message ***
--------------------------------------------------------------------------
mpirun noticed that process rank 1 with PID 24282 on node julian-Pc exited on signal 8 (Floating point exception).
--------------------------------------------------------------------------
[0] #0  Foam::error::printStack(Foam::Ostream&) at ??:?
[0] #1  Foam::sigFpe::sigHandler(int) at ??:?
[0] #2   in "/lib/x86_64-linux-gnu/libc.so.6"
[0] #3  void Foam::vtkSurfaceWriter::writeData<double>(Foam::Ostream&, Foam::Field<double> const&) at ??:?
[0] #4  void Foam::vtkSurfaceWriter::writeTemplate<double>(Foam::fileName const&, Foam::fileName const&, Foam::Field<Foam::Vector<double> > const&, Foam::List<Foam::face> const&, Foam::word const&, Foam::Field<double> const&, bool, bool) const at ??:?
[0] #5  void Foam::sampledSurfaces::writeSurface<double>(Foam::Field<double> const&, int, Foam::word const&, Foam::fileName const&) at ??:?
[0] #6  void Foam::sampledSurfaces::sampleAndWrite<double>(Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&) at ??:?
[0] #7  void Foam::sampledSurfaces::sampleAndWrite<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> >(Foam::IOobjectList const&) at ??:?
[0] #8  Foam::sampledSurfaces::write() at ??:?
[0] #9  
[0]  at ??:?
[0] #10  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
[0] #11  
[0]  at ??:?
[julian-Pc:24986] *** Process received signal ***
[julian-Pc:24986] Signal: Floating point exception (8)
[julian-Pc:24986] Signal code:  (-6)
[julian-Pc:24986] Failing at address: 0x3e80000619a
[julian-Pc:24986] [ 0] /lib/x86_64-linux-gnu/libc.so.6(+0x36ff0) [0x7fba2e5ffff0]
[julian-Pc:24986] [ 1] /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x37) [0x7fba2e5fff77]
[julian-Pc:24986] [ 2] /lib/x86_64-linux-gnu/libc.so.6(+0x36ff0) [0x7fba2e5ffff0]
[julian-Pc:24986] [ 3] /opt/openfoam222/platforms/linux64GccDPOpt/lib/libsampling.so(_ZN4Foam16vtkSurfaceWriter9writeDataIdEEvRNS_7OstreamERKNS_5FieldIT_EE+0x81) [0x7fba303dac91]
[julian-Pc:24986] [ 4] /opt/openfoam222/platforms/linux64GccDPOpt/lib/libsampling.so(_ZNK4Foam16vtkSurfaceWriter13writeTemplateIdEEvRKNS_8fileNameES4_RKNS_5FieldINS_6VectorIdEEEERKNS_4ListINS_4faceEEERKNS_4wordERKNS5_IT_EEbb+0x248) [0x7fba303dbcf8]
[julian-Pc:24986] [ 5] /opt/openfoam222/platforms/linux64GccDPOpt/lib/libsampling.so(_ZN4Foam15sampledSurfaces12writeSurfaceIdEEvRKNS_5FieldIT_EEiRKNS_4wordERKNS_8fileNameE+0x31b) [0x7fba303a341b]
[julian-Pc:24986] [ 6] /opt/openfoam222/platforms/linux64GccDPOpt/lib/libsampling.so(_ZN4Foam15sampledSurfaces14sampleAndWriteIdEEvRKNS_14GeometricFieldIT_NS_12fvPatchFieldENS_7volMeshEEE+0x13c) [0x7fba303a589c]
[julian-Pc:24986] [ 7] /opt/openfoam222/platforms/linux64GccDPOpt/lib/libsampling.so(_ZN4Foam15sampledSurfaces14sampleAndWriteINS_14GeometricFieldIdNS_12fvPatchFieldENS_7volMeshEEEEEvRKNS_12IOobjectListE+0x22e) [0x7fba303a6c1e]
[julian-Pc:24986] [ 8] /opt/openfoam222/platforms/linux64GccDPOpt/lib/libsampling.so(_ZN4Foam15sampledSurfaces5writeEv+0x10c) [0x7fba3039f8bc]
[julian-Pc:24986] [ 9] sample() [0x4049c5]
[julian-Pc:24986] [10] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5) [0x7fba2e5eade5]
[julian-Pc:24986] [11] sample() [0x40579a]
[julian-Pc:24986] *** End of error message ***
--------------------------------------------------------------------------
mpirun noticed that process rank 0 with PID 24986 on node julian-Pc exited on signal 8 (Floating point exception).
--------------------------------------------------------------------------

As I understand, there is some problem with the GAMG solver for p, which causes a floating point exception?
Can anyone give me a hint, what this does mean, and what I have to change?

Thanks and best regards
Julian

[Ruli]

Dear Foamers,

as always, it was a mesh quality based error, which got fixed by mesh refinement...

Best regards
Julian

[pbachant]

Originally Posted by Ruli

Dear Foamers,

as always, it was a mesh quality based error, which got fixed by mesh refinement...

Best regards
Julian

What was the output of checkMesh for the failed case? I'm having similar issues, but checkMesh says the mesh is fine.

[Ruli]

Dear Pete,

I don`t have the log anymore, but I remember, the mistake vanished, when I refined my basic blockMesh a little bit and I am quite sure, it was the mesh quality at the rotor blade`s trailing edge, which caused the problem.

Another thing, which might help: Try pre-calculating with potentialFoam.

Best regards Julian