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-   -   time step continuity errors?? (http://www.cfd-online.com/Forums/openfoam-solving/65714-time-step-continuity-errors.html)

CFT June 23, 2009 23:48

time step continuity errors??
 
Dear all
I am running a simulation of a building using the k epsilon rng model. However on running the first time step I get a "time step continuity error"

Does anyone know what the problem is.

thanks
CFT

The error message is as follows
Starting time loop

Time = 1.01

DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 0.00508, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 1, Final residual = 0.00557, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 1, Final residual = 0.00508, No Iterations 1
DICPCG: Solving for p, Initial residual = 1, Final residual = 0.00923, No Iterations 298
time step continuity errors : sum local = 3.61e-05, global = 1.98e-07, cumulative = 1.98e-07
#0 Foam::error::printStack(Foam::Ostream&) in "/home/steven/OpenFOAM/OpenFOAM-1.5/lib/linuxGccDPOpt/libOpenFOAM.so"
#1 Foam::sigFpe::sigFpeHandler(int) in "/home/st/OpenFOAM/OpenFOAM-1.5/lib/linuxGccDPOpt/libOpenFOAM.so"
#2 Uninterpreted: [0xffffe400]
#3 Foam::divide(Foam::Field<double>&, Foam::UList<double> const&, Foam::UList<double> const&) in "/home/st/OpenFOAM/OpenFOAM-1.5/lib/linuxGccDPOpt/libOpenFOAM.so"
#4 void Foam::divide<Foam::fvPatchField, Foam::volMesh>(Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh>&, Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&) in "/home/st/OpenFOAM/OpenFOAM-1.5/lib/linuxGccDPOpt/libincompressibleRASModels.so"
#5 Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam::operator/<Foam::fvPatchField,Foam::volMesh>(Foam::tmp<Foam: :GeometricField<double, Foam::fvPatchField, Foam::volMesh> > const&, Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&) in "/home/st/OpenFOAM/OpenFOAM-1.5/lib/linuxGccDPOpt/libincompressibleRASModels.so"
#6 Foam::incompressible::RASModels::RNGkEpsilon::corr ect() in "/home/st/OpenFOAM/OpenFOAM-1.5/lib/linuxGccDPOpt/libincompressibleRASModels.so"
#7 main in "/home/st/OpenFOAM/OpenFOAM-1.5/applications/bin/linuxGccDPOpt/simpleFoam"
#8 __libc_start_main in "/lib/libc.so.6"
#9 Foam::regIOobject::readIfModified() in "/home/st/OpenFOAM/OpenFOAM-1.5/applications/bin/linuxGccDPOpt/simpleFoam"
Floating point exception

hellorishi June 24, 2009 09:01

Hi,

I guess it might be a problem of Initial/Boundary condition. Check if you have initalised everything correctly? Seems like a division by ZERO problem.( maybe Pressure?)

Are you starting simulation from timestep 1.00?

wolle1982 June 26, 2009 09:29

hellorishi is right, i almost always is a BC problem. make sure for the simplefoam you have the fvscheme on stady state, not on euler.
make sure you have the turbulence on/off (at beginning sometimes good to have it off)

go to a more aggressive divscheme

check BC again. U in right direction? initial k or initial epsilon too big?? calculate them in the first place.


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