[feijooos]

Hi All,

I was running the dnsFoam tutorial case on a 128^3 mesh and I am running into some issues.

I get the following error msg:

Time = 0.175

Number of forced K = 12
k(0.175) = 1.12316e+48
epsilon(0.175) = 2.81871e+49
U.f(0.175) = -1.60366e+22
#0 Foam::error:rintStack(Foam::Ostream&) in "/usr/local/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/lib
OpenFOAM.so"
#1 Foam::sigFpe::sigFpeHandler(int) in "/usr/local/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOA
M.so"
#2 ?? in "/lib64/libc.so.6"
#3 Foam::PBiCG::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const in "/usr/l
ocal/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"
#4 Foam::fvMatrix<Foam::Vector<double> >::solve(Foam::Istream&) in "/usr/local/OpenFOAM/OpenFOAM-1.5/ap
plications/bin/linux64GccDPOpt/dnsFoam"
#5 main in "/usr/local/OpenFOAM/OpenFOAM-1.5/applications/bin/linux64GccDPOpt/dnsFoam"
#6 __libc_start_main in "/lib64/libc.so.6"
#7 Foam::regIOobject::readIfModified() in "/usr/local/OpenFOAM/OpenFOAM-1.5/applications/bin/linux64Gcc
DPOpt/dnsFoam"


k and eps seem to go completely off the chart, do you have any idea what is going on?

Thanks!

[cfdmarkus]

Hi

I also tested dnsFOAM a while and I had to reduce the time step for finer meshes!

I always thought that dnsFoam does not work in parallel. Do you run your 128^3 on a single processor?

I am very interested in your results, since I was never able to successfully use dnsFOAM. Are you getting a nice energy spectrum and do you know who to set the parameters for a certain Reynolds number?

Best regards
Markus

[feijooos]

Hey Markus,

Yeah that makes sense, I'll reduce the time step.

I also found out that dnsFoam doesn't work in parallel. I submitted the 128^3 case to one processor. It is not ideal, but it seems to be working.

I just started looking at dnsFoam so I don't know anything about setting the Re #, but I'll share my results for E(k) when the case is finished.

Eelco

[cfdmarkus]

Hi Eelco,

how are you getting on with dnsFoam, have you managed to get reasonable results?

I am still struggeling to get anything that looks like a energy spectrum !!

Regards
Markus

[feijooos]

Hey Markus,

I am struggling to get anything remotely close to a reasonable energy spectrum as well.
The solver takes way too long to get a decent calculation done. Although it uses a spectral method, the fact that it cannot be used in parallel is not good. I am trying to figure out a way for it to work in parallel, but it's taking some time to understand the solver completely.

Regard, Eelco

[cfdmarkus]

Hi Eelco,

I found a bug in dnsFOAM see here:
http://www.cfd-online.com/Forums/ope...g-dnsfoam.html

If you fix the bug you will get a nice energy spectra, providing the forcing parameters are set correctly.

Markus

[feijooos]

Hey Markus,

Thanks for letting me know. I appreciate it.
I'll try to some cases with this modification.

Eelco