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Old   April 23, 2012, 06:15
Default effect of nonlinear terms
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Farshad
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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:rintStack(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:perator/<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
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Old   April 24, 2012, 11:42
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Daniel P. Combest
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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
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Old   April 24, 2012, 13:41
Default explicit nonlinear term
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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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