[casseer15]

Hello,


I'm trying to simulate the combustion of a simple case of H2 combustion with air in a square container of 12m x 3m x 3m. I set the ignition at the middle, and tried to simulate a case with o.75 equivalence ratio with inhomogenous method. The mesh is a entirely hexagonal mesh. LES with KEqn SGS model is used. I use pimple with 4 iteration steps. Solver is GAMG. I tried PCG as well, but got same result.



I tried different meshes (40mm, 20mm, 30mm) but always I get an error and calculation stops after about 0.02 seconds. At this time I noticed that b goes t negative values, which is impossible. I have used limitedlinear01 as the div scheme for b, so it should essentially limit b within 0 and 1, but it doesn't seem to happen here.

I always get the below error.


can anyone please shed any light on what the error can be.


#0 Foam::error:rintStack(Foam::Ostream&) at ??:?
#1 Foam::sigFpe::sigHandler(int) at ??:?
#2 ? in "/lib/x86_64-linux-gnu/libc.so.6"
#3 double Foam::sumProd<double>(Foam::UList<double> const&, Foam::UList<double> const&) at ??:?
#4 Foam::PBiCGStab::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
#5 Foam::GAMGSolver::solveCoarsestLevel(Foam::Field<d ouble>&, Foam::Field<double> const&) const at ??:?
#6 Foam::GAMGSolver::Vcycle(Foam::PtrList<Foam::lduMa trix::smoother> const&, Foam::Field<double>&, Foam::Field<double> const&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::PtrList<Foam::Field<double> >&, Foam::PtrList<Foam::Field<double> >&, unsigned char) const at ??:?
#7 Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
#8 Foam::fvMatrix<double>::solveSegregated(Foam::dict ionary const&) at ??:?
#9 Foam::fvMatrix<double>::solve(Foam::dictionary const&) in "/opt/openfoam9/platforms/linux64GccDPInt32Opt/bin/XiFoam"
#10 Foam::fvMatrix<double>::solve() in "/opt/openfoam9/platforms/linux64GccDPInt32Opt/bin/XiFoam"
#11 ? in "/opt/openfoam9/platforms/linux64GccDPInt32Opt/bin/XiFoam"
#12 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#13 ? in "/opt/openfoam9/platforms/linux64GccDPInt32Opt/bin/XiFoam"


I can't wrap my head around what is happening and has been stuck here for a couple of weeks, so any help is greatly appreciated.

[casseer15]

Anyone can give me some idea on this please?

[Sarah13]

Hi
Did you find any insights on this issue? I am also getting negative values of b, specifically in case of 3D simulations, that doesn't seem to happen with 2D cases.