[twoofspade]

Dear All,

I am practically new with OpenFoam software. I have been learning to using it in the last 1 year, and I am very interested to learn more.

I have been trying to run simpleFoam for my case. A simply inlet - outlet problem (Please See Picture ).

I utilised enGrid to generate my mesh, convert it to OF format and run the "simpleFoam" command.

For the laminar case, it ran well. The model is converged after 2.08 Secs (0.01 Time steps). Results look brilliant.

Then, I tried to run the same model wit additional turbulence model (k E Model). Unfortunately the model stops after 3.364 Secs.

It says:

...
Time = 3.364


DILUPBiCG: Solving for Ux, Initial residual = 0.000896092, Final residual = 5.61209e-05, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.000474927, Final residual = 2.49001e-05, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 6.89077e-05, Final residual = 8.59384e-06, No Iterations 1
#0 Foam::error:rintStack(Foam::Ostream&) in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#1 Foam::sigFpe::sigHandler(int) in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#2 in "/lib64/libc.so.6"
#3 Foam:ICPreconditioner::calcReciprocalD(Foam::Fie ld<double>&, Foam::lduMatrix const&) in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#4 Foam:ICPreconditioner:ICPreconditioner(Foam::l duMatrix::solver const&, Foam::dictionary const&) in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#5 Foam::lduMatrix:reconditioner::addsymMatrixConst ructorToTable<Foam:ICPreconditioner>::New(Foam:: lduMatrix::solver const&, Foam::dictionary const&) in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#6 Foam::lduMatrix:reconditioner::New(Foam::lduMatr ix::solver const&, Foam::dictionary const&) in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#7 Foam::PCG::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#8 Foam::fvMatrix<double>::solve(Foam::dictionary const&) in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libfiniteVolume.so"
#9
in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/bin/simpleFoam"
#10 __libc_start_main in "/lib64/libc.so.6"
#11
at /home/abuild/rpmbuild/BUILD/glibc-2.14.1/csu/../sysdeps/x86_64/elf/start.S:116
Floating point exception
....

So, please anyone can give me some hints ? Where the problem lies?

Thank you very much in advance for all helps.

My best regards,


Twoofspade

[RodriguezFatz]

Can you post the log of the previous time step?

[Alfalfa]

It seems like you try to have a transient solution (short time step), but simpleFoam is a steady-state solver, so you can use time step of 1. For transient you would be better with pisoFoam I think. As for the problem itself, we would indeed need the previous time step.

[twoofspade]

Guys, thank you for the reply.

My best regards

Two time steps before crash:

Time = 3.36

DILUPBiCG: Solving for Ux, Initial residual = 0.0277148, Final residual = 0.000851706, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.091094, Final residual = 0.00285158, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.00907594, Final residual = 0.000225789, No Iterations 2
DICPCG: Solving for p, Initial residual = 0.838731, Final residual = 0.00315672, No Iterations 2
time step continuity errors : sum local = 3.0336e+18, global = 3.44016e+09, cumulative = 1.4522e+10
DILUPBiCG: Solving for epsilon, Initial residual = 0.999998, Final residual = 0.0524514, No Iterations 2
bounding epsilon, min: -7.24117e+31 max: 1.01235e+48 average: 3.33586e+42
DILUPBiCG: Solving for k, Initial residual = 0.958669, Final residual = 0.0505108, No Iterations 2
bounding k, min: -1.40113e+20 max: 2.67559e+38 average: 9.44339e+32
ExecutionTime = 26853.5 s ClockTime = 26871 s

Time = 3.362

DILUPBiCG: Solving for Ux, Initial residual = 0.00134929, Final residual = 1.56893e-07, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.000234047, Final residual = 2.64696e-06, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.0001284, Final residual = 1.14291e-08, No Iterations 1
DICPCG: Solving for p, Initial residual = 0.857322, Final residual = 0.00597814, No Iterations 7
time step continuity errors : sum local = 1.99334e+28, global = -3.04947e+15, cumulative = -3.04946e+15
DILUPBiCG: Solving for epsilon, Initial residual = 1.84425e-05, Final residual = 5.74803e-10, No Iterations 1
bounding epsilon, min: -1.36285e+53 max: 1.13316e+73 average: 5.04708e+67
DILUPBiCG: Solving for k, Initial residual = 0.000186333, Final residual = 8.09215e-06, No Iterations 1
bounding k, min: -1.06037e+36 max: 9.30235e+52 average: 6.5853e+47
ExecutionTime = 26860.8 s ClockTime = 26879 s

Time = 3.364

DILUPBiCG: Solving for Ux, Initial residual = 0.000896092, Final residual = 5.61209e-05, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.000474927, Final residual = 2.49001e-05, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 6.89077e-05, Final residual = 8.59384e-06, No Iterations 1
#0 Foam::error:rintStack(Foam::Ostream&) in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#1 Foam::sigFpe::sigHandler(int) in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#2 in "/lib64/libc.so.6"
#3 Foam:ICPreconditioner::calcReciprocalD(Foam::Fie ld<double>&, Foam::lduMatrix const&) in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#4 Foam:ICPreconditioner:ICPreconditioner(Foam::l duMatrix::solver const&, Foam::dictionary const&) in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#5 Foam::lduMatrix:reconditioner::addsymMatrixConst ructorToTable<Foam:ICPreconditioner>::New(Foam:: lduMatrix::solver const&, Foam::dictionary const&) in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#6 Foam::lduMatrix:reconditioner::New(Foam::lduMatr ix::solver const&, Foam::dictionary const&) in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#7 Foam::PCG::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#8 Foam::fvMatrix<double>::solve(Foam::dictionary const&) in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libfiniteVolume.so"
#9
in "/opt/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/bin/simpleFoam"
#10 __libc_start_main in "/lib64/libc.so.6"
#11
at /home/abuild/rpmbuild/BUILD/glibc-2.14.1/csu/../sysdeps/x86_64/elf/start.S:116
Floating point exception

[Wokl]

Hey,

i think you have a Problem with ur boundary conditions for k and epsilon. How did you calculate the values for them? what boundary conditions did you set?

I'm also pretty new to cfd, so this might not be the right answer.

This link shows how to calculate the values.
http://www.cfd-online.com/Wiki/Turbu...ary_conditions

christian