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-   -   effect of nonlinear terms (http://www.cfd-online.com/Forums/openfoam/100287-effect-nonlinear-terms.html)

Farshad_Noravesh April 23, 2012 06:15

effect of nonlinear terms
 
Hi,

I have a problem when i add a nonlinear term(quadratic term) inside my source term and openfoam gets error. what is the best config for fvsolution and fvschemes for these nonlinear effects?
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 1.10082e-06, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 1, Final residual = 1.23009e-06, No Iterations 1
DILUPBiCG: Solving for c, Initial residual = 1, Final residual = 2.55268e-06, No Iterations 1
min(c) = 0
DILUPBiCG: Solving for sigma, Initial residual = 1, Final residual = 1.84628e-06, No Iterations 3
max(sigma) = 1
DILUPBiCG: Solving for hu, Initial residual = 1.61405e-05, Final residual = 5.77265e-11, No Iterations 1
DILUPBiCG: Solving for h, Initial residual = 0.999974, Final residual = 2.25102e-06, No Iterations 1
DICPCG: Solving for p, Initial residual = 1, Final residual = 9.19628e-07, No Iterations 32
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 6.16706e-14, global = -5.94702e-15, cumulative = -5.94702e-15
DILUPBiCG: Solving for k, Initial residual = 1, Final residual = 1.28008e-06, No Iterations 1
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for Ux, Initial residual = 0.196429, Final residual = 1.12715e-07, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.111858, Final residual = 3.43147e-08, No Iterations 1
DILUPBiCG: Solving for c, Initial residual = 0.283645, Final residual = 4.53729e-07, No Iterations 1
min(c) = 0
#0 Foam::error::printStack(Foam::Ostream&) in "/home/farshad/OpenFOAM/OpenFOAM-1.7.1/lib/linux64GccDPOpt/libOpenFOAM.so"
#1 Foam::sigFpe::sigFpeHandler(int) in "/home/farshad/OpenFOAM/OpenFOAM-1.7.1/lib/linux64GccDPOpt/libOpenFOAM.so"
#2 in "/lib64/libc.so.6"
#3 Foam::divide(Foam::Field<double>&, Foam::UList<double> const&, Foam::UList<double> const&) in "/home/farshad/OpenFOAM/OpenFOAM-1.7.1/lib/linux64GccDPOpt/libOpenFOAM.so"
#4 Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam::operator/<Foam::fvPatchField, Foam::volMesh>(Foam::tmp<Foam::GeometricField<doub le, Foam::fvPatchField, Foam::volMesh> > const&, Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > const&) in "/home/farshad/OpenFOAM/OpenFOAM-1.7.1/applications/bin/linux64GccDPOpt/fsd1"
#5
in "/home/farshad/OpenFOAM/OpenFOAM-1.7.1/applications/bin/linux64GccDPOpt/fsd1"
#6 __libc_start_main in "/lib64/libc.so.6"
#7
at /usr/src/packages/BUILD/glibc-2.11.3/csu/../sysdeps/x86_64/elf/start.S:116
Floating point exception
farshad@linux-0dde:~/OpenFOAM/farshad-1.7.1/run/flamesurfacedensity1>

Kind Regards,

Farshad

chegdan April 24, 2012 11:42

Farshad,

Are you adding an implicit of explicit nonlinear term? After all, the linear system solvers only solve the linear system and can't solve nonlinear implicit terms. You will have to "linearize" your nonlinear term if you want it as an implicit term.

More info is helpful.

Dan

Farshad_Noravesh April 24, 2012 13:41

explicit nonlinear term
 
Dear Chegdan,

Thank you very much for your post. I need to add an explicit nonlinear term to the end of flame surface density model developed by Prof.Hawkes and Prof.Cant.

Is it possible to solve it without linearizing the pde?

Kind Regards,

Farshad


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