[Elol]

Hello Foam experts,

I am calculating new volScalarField kl as follows;

const Time& runTime = mesh_.time();
volScalarField varible = fvc::laplacian(sumAlpha);
volScalarField::Internal varible2 = varible.ref();
scalarField varible3 = mesh_.V();
volScalarField::Internal varible4 = sumAlpha.ref();

 volScalarField kl =  ((alphaMax_ - sumAlpha) / runTime.deltaT().value()) / ( varible)     ;

where alplhaMax_ is scalar and sumAlpha is volScalarField.

to use it in the next transport equation;

 fvScalarMatrix alphatEqn
            (
                fvm::ddt(alphas_)
              - fvm::laplacian(kl , alphas_) 
            );

            alphatEqn.solve(mesh_.solver("alphatDiffusion"));

where alphas_ is volScalarField as well,

it is compiling perfectly however, when I run a case i have the following error

#0  Foam::error::printStack(Foam::Ostream&) at ??:?
#1  Foam::sigFpe::sigHandler(int) at ??:?
#2  ? in "/lib/x86_64-linux-gnu/libc.so.6"
#3  Foam::divide(Foam::Field<double>&, Foam::UList<double> const&, Foam::UList<double> const&) at ??:?
#4  Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam::operator/<Foam::fvPatchField, Foam::volMesh>(Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > const&, Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&) in "/home/Elol/OpenFOAM/Elol-v1712/platforms/linux64GccDPInt32Opt/bin/multiphaseFoam"
#5  Foam::multiphaseDriftMixture::solveAlphas() at ??:?
#6  Foam::multiphaseDriftMixture::solve() at ??:?
#7  ? in "/home/Elol/OpenFOAM/Elol-v1712/platforms/linux64GccDPInt32Opt/bin/multiphaseFoam"
#8  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#9  ? in "/home/Elol/OpenFOAM/Elol-v1712/platforms/linux64GccDPInt32Opt/bin/multiphaseFoam"
Floating point exception (core dumped)

I can not find why?

I think the problem some how is locating in the fvc::laplacian(sumAlpha) which I dont understand what the explicit laplacian generates.

anybody for help.

Elol

[mAlletto]

seem a division by zero. If you divide by something you have to be sure it's never zero. So instead doing A/B it is better doing A/(B + small). small is a field which small value and the correct dimension

[Elol]

Hi Michael,

Thanks, It worked.

Best Regards
Elol

[mAlletto]

For a good book regarding the numeric in OF see https://www.springer.com/de/book/9783319168739