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-   -   Convergence troubles (https://www.cfd-online.com/Forums/openfoam-solving/59546-convergence-troubles.html)

 guimch July 18, 2007 04:23

Hi everybody ! Yesterday, I s

Hi everybody !
Yesterday, I started a new thread about the same subject but I'm afraid I wasn't clear enough. So let me remind you what is going wrong.
I have to compare results given by Fluent and OpenFoam in an industrial test case. I used fluentMeshtoFoam to use the same mesh as fluent to make my comparison possible.checkMesh told me that at this point everything is ok. I am using the simpleFoam solver since my flow is incompressible, steady state and turbulent. My inlet is a non-uniform velocity field (a swirl whose max velocity amounts to 12 m/s). Using paraView, I could check that my swirl is well modeled. When I turn the option "turbulence" off, Foam start the calculation without any trouble. But when "turbulence" is on, I get the following error message :

Create mesh for time = 0

Selecting incompressible transport model CrossPowerLaw
Selecting turbulence model kEpsilon

Starting time loop

Time = 1

DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 0.0291, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 1, Final residual = 0.0176, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 1, Final residual = 0.0124, No Iterations 1
AMG: Solving for p, Initial residual = 1, Final residual = 1, No Iterations 0
AMG: Solving for p, Initial residual = 1, Final residual = 1, No Iterations 0
time step continuity errors : sum local = 1.59e+06, global = 1.59e+06, cumulative = 1.59e+06
#0 Foam::error::printStack(Foam:http://www.cfd-online.com/OpenFOAM_D...part/proud.gifstream&)
#1 Foam::sigFpe::sigFpeHandler(int)
#2 Uninterpreted: [0x2ee420]
#3 Foam::divide(Foam::Field<double>&, Foam::UList<double> const&, Foam::UList<double> const&)
#4 void Foam::divide<foam::fvpatchfield,>(Foam::GeometricF ield<double,>&, Foam::GeometricField<double,> const&, Foam::GeometricField<double,> const&)
#5 Foam::tmp<foam::geometricfield<double,> > Foam::operator/<foam::fvpatchfield,>(Foam::tmp<foam::geometricfie ld<double,> > const&, Foam::GeometricField<double,> const&)
#6 Foam::turbulenceModels::kEpsilon::correct()
#7 main
#8 __libc_start_main
#9 __gxx_personality_v0 at ../sysdeps/i386/elf/start.S:122
Floating exception

It seems to be a convergence trouble... So,
I had a look on advices given in the Message Board about the same kind of problem, I change some parameters as shown on message but Foam keep on telling me the same message.
I hope that someone could help me because I haven't got idea anymore.

Thanks you !
Guillaume

 gschaider July 25, 2007 13:19

See the answer in the other th