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-   -   error message after running icoFoam (http://www.cfd-online.com/Forums/openfoam-solving/97148-error-message-after-running-icofoam.html)

Ahmed Khattab February 9, 2012 17:35

error message after running icoFoam
 
Dear Foamers,

while running case on OpenFOAM by icoFoam solver I've gotten this message but i could not understand exatcly where problem is? please help:)

Courant Number mean: 0.395781 max: 2.36188e+294
#0 Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam210/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#1 Foam::sigFpe::sigHandler(int) in "/opt/openfoam210/platforms/linuxGccDPOpt/lib/libOpenFOAM.so"
#2 Uninterpreted:
#3 void Foam::fvc::surfaceIntegrate<Foam::Vector<double> >(Foam::Field<Foam::Vector<double> >&, Foam::GeometricField<Foam::Vector<double>, Foam::fvsPatchField, Foam::surfaceMesh> const&) in "/opt/openfoam210/platforms/linuxGccDPOpt/lib/libfiniteVolume.so"
#4 Foam::tmp<Foam::GeometricField<Foam::Vector<double >, Foam::fvPatchField, Foam::volMesh> > Foam::fvc::surfaceIntegrate<Foam::Vector<double> >(Foam::GeometricField<Foam::Vector<double>, Foam::fvsPatchField, Foam::surfaceMesh> const&) in "/opt/openfoam210/platforms/linuxGccDPOpt/lib/libfiniteVolume.so"
#5 Foam::tmp<Foam::GeometricField<Foam::Vector<double >, Foam::fvPatchField, Foam::volMesh> > Foam::fvc::div<Foam::Vector<double> >(Foam::GeometricField<Foam::Vector<double>, Foam::fvsPatchField, Foam::surfaceMesh> const&) in "/opt/openfoam210/platforms/linuxGccDPOpt/lib/libfiniteVolume.so"
#6 Foam::fv::gaussLaplacianScheme<Foam::Vector<double >, double>::fvmLaplacian(Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&, Foam::GeometricField<Foam::Vector<double>, Foam::fvPatchField, Foam::volMesh> const&) in "/opt/openfoam210/platforms/linuxGccDPOpt/lib/libfiniteVolume.so"
#7
in "/opt/openfoam210/platforms/linuxGccDPOpt/bin/icoFoam"
#8
in "/opt/openfoam210/platforms/linuxGccDPOpt/bin/icoFoam"
#9
in "/opt/openfoam210/platforms/linuxGccDPOpt/bin/icoFoam"
#10
in "/opt/openfoam210/platforms/linuxGccDPOpt/bin/icoFoam"
#11 __libc_start_main in "/lib/i386-linux-gnu/libc.so.6"
#12
in "/opt/openfoam210/platforms/linuxGccDPOpt/bin/icoFoam"
Floating point exception

BernhardGrieser February 10, 2012 03:48

Quote:

Originally Posted by rebel ahmed (Post 343666)
Dear Foamers,
while running case on OpenFOAM by icoFoam solver I've gotten this message but i could not understand exatcly where problem is? please help:)

Courant Number mean: 0.395781 max: 2.36188e+294

Courant Number too high. Physical velocity exceeds "numerical" velocity. Smaller time step required.

Ahmed Khattab February 10, 2012 14:38

too high courant number
 
i tried to adjust time step and cell size. but not working.

also i see that mean courant is about 0.3.

cfd-noob February 10, 2012 15:45

Last time I saw that it was a because of a singularity.

Your mean value is pretty low compared to the maximum. You can try to watch the result with paraView and maybe make a bigger radius at the point of the Maximum if this is possible.

francesco_capuano February 10, 2012 16:27

The floating point exception error occurs when the solution contains NaNs (Not a Number). To prevent meaningless solutions, OpenFOAM is provided with a floating point exception trapping represented by the environment variable $FOAM_SIGFPE: when active, the solution stops as soon as a NaN appears in the field. If you wish to let the solver continue running, you can unset FOAM_SIGFPE by commenting its definition within the /etc/bashrc file (you will need to restart your shell).

However, it is evident that your singularity is caused by the high Courant number, therefore I would suggest that you first check your boundary and initial conditions and reduce (as already suggested) your time-step. Starting from a very small time-step (e.g. 1e-10s) sometimes works, at least in my experience :D

Cheers,
Francesco


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