[WUYing]

Hi, I have met a convergence problem in OF when simulating the FSI of cylinder. The CFL becomes larger until around 30,000 at the last timestep before crash. I also checked the pressure and velocity fields in Paraview and find they are obviously unreasonable at the very beginning.

The following is the error report:

#0  Foam::error::printStack(Foam::Ostream&) at ??:?
#1  Foam::sigFpe::sigHandler(int) at ??:?
#2  ? in "/lib/x86_64-linux-gnu/libc.so.6"
#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 ??:?
#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::Field<double>&, Foam::Field<double>&, Foam::PtrList<Foam::Field<double> >&, Foam::PtrList<Foam::Field<double> >&, unsigned char) const at ??:?
#5  Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
#6  Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&) at ??:?
#7  Foam::fvMatrix<double>::solve(Foam::dictionary const&) in "/home/ying/OpenFOAM41/OpenFOAM-4.1/platforms/linux64GccDPInt32Opt/bin/pimpleDyMFoam"
#8  ? in "/home/ying/OpenFOAM41/OpenFOAM-4.1/platforms/linux64GccDPInt32Opt/bin/pimpleDyMFoam"
#9  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#10  ? in "/home/ying/OpenFOAM41/OpenFOAM-4.1/platforms/linux64GccDPInt32Opt/bin/pimpleDyMFoam"
Floating point exception (core dumped)

I check the similar posts like:
Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam222/platforms/linux64GccDPOp
https://www.simscale.com/forum/t/cfd...-failing/82914
https://www.salome-platform.org/foru...m_10/549857363

but very limited information can be obtained....

I use a refine mesh to rerun and the case can last for more time steps (coarse mesh crash at time = 1.8 and refine mesh crash at time=18) but U and P are still incorrect at the very beginning.

The attachments include:
(1) case.zip:
0.zip (U, p, pointDisplacement)
system.zip (controlDict, fvScheme, fvSolution)
constant.zip (dynamicMeshDict, transportProperties, turbulenceProperties)
(2) log.zip (log.pimpleDyMFoam file)
(3) coarse.zip (coarse mesh, and corresponding (U, p) images at last timestep)
(4) refine.zip (refine mesh, and corresponding (U, p) images at last timestep)

Due to the size limit, I cannot upload my mesh and animation of flow fields, please send me email if you want to obtain the complete case file.

I am very appreciated for any suggestion!