time step continuity errors??

CFT · June 24, 2009, 00:48

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:

rintStack(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:

perator/<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, 10:01

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, 10:29

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.

June 24, 2009, 00:48	time step continuity errors??	#1
CFT New Member CFT Join Date: Mar 2009 Posts: 15 Rep Power: 17	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:rintStack(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:perator/<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

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June 24, 2009, 10:01		#2
hellorishi Senior Member Rishi . Join Date: Mar 2009 Posts: 149 Rep Power: 17	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?

June 26, 2009, 10:29		#3
wolle1982 Senior Member Wolfgang Heydlauff Join Date: Mar 2009 Location: Germany Posts: 136 Rep Power: 21	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.