[taalf]

Hello everybody,

I'm proud to post my first comment in this forum . I don't speak English so good so I apologize for every English mistakes .

And, to show how much I am motivated, I will put pictures in my post : I set a good example, isn't it ?

Ok, I'm a false beginner in OpenFOAM that I study for my Final Project and it happens something that I don't understand and that I very would like to solve.

My problem is that when I make a coarse blockMesh geometry for a own icoFoam case, it works, but when I use a finer mesh, it makes an "Exception en virgule flottante" during calculation after very few first iterations.

Here is my coarse case (a 2D case with 2 "empty" boundary conditions and only one cell in the z direction) :



with, in my transportProperties file :

transportModel  Newtonian;

nu              nu [0 2 -1 0 0 0 0] 1e-06;

and, in my controlDict file :

application     icoFoam;

startFrom       startTime;

startTime       0;

stopAt          endTime;

endTime         1;

deltaT          0.001;

writeControl    timeStep;

writeInterval   100;

and the results :



Pretty good, isn't it ?

Then, I tried to use a finer mesh by only modifying the simpleGrading values in the blockMeshDict:



but this happens when I launch icoFoam after deleting the old time directories (0 0.1 0.2 etc.) :

Time = 0.011

Courant Number mean: 1.01727e+34 max: 7.44368e+37
DILUPBiCG:  Solving for Ux, Initial residual = 5.77125e-09, Final residual = 5.77125e-09, No Iterations 0
DILUPBiCG:  Solving for Uy, Initial residual = 2.41172e-09, Final residual = 2.41172e-09, No Iterations 0
#0  Foam::error:: printStack(Foam::Ostream&) in "/opt/openfoam171/lib/linuxGccDPOpt/libOpenFOAM.so"
#1  Foam::sigFpe::sigFpeHandler(int) in "/opt/openfoam171/lib/linuxGccDPOpt/libOpenFOAM.so"
#2  Uninterpreted: 
#3  Foam:: DICPreconditioner::calcReciprocalD(Foam::Field<double>&, Foam::lduMatrix const&) in "/opt/openfoam171/lib/linuxGccDPOpt/libOpenFOAM.so"
#4  Foam:: DICPreconditioner:: DICPreconditioner(Foam::lduMatrix::solver const&, Foam::dictionary const&) in "/opt/openfoam171/lib/linuxGccDPOpt/libOpenFOAM.so"
#5  Foam::lduMatrix:: preconditioner::addsymMatrixConstructorToTable<Foam:: DICPreconditioner>::New(Foam::lduMatrix::solver const&, Foam::dictionary const&) in "/opt/openfoam171/lib/linuxGccDPOpt/libOpenFOAM.so"
#6  Foam::lduMatrix:: preconditioner::New(Foam::lduMatrix::solver const&, Foam::dictionary const&) in "/opt/openfoam171/lib/linuxGccDPOpt/libOpenFOAM.so"
#7  Foam::PCG::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const in "/opt/openfoam171/lib/linuxGccDPOpt/libOpenFOAM.so"
#8  Foam::fvMatrix<double>::solve(Foam::dictionary const&) in "/opt/openfoam171/lib/linuxGccDPOpt/libfiniteVolume.so"
#9  
 in "/opt/openfoam171/applications/bin/linuxGccDPOpt/icoFoam"
#10  __libc_start_main in "/lib/libc.so.6"
#11  
 in "/opt/openfoam171/applications/bin/linuxGccDPOpt/icoFoam"
Exception en point flottant

Even if I reduce the time between iterations :

deltaT          0.0000001;

it stops after few iterations with the same error.

My extraordinary happiness when I computed my first case totally collapsed when I realized I wasn't able to redo it with fine mesh !

Does somebody have an idea ?