[pakanatiakash]

Hi All

I am working on a multiphase solidification model and I need to construct a drag model taking into grain motion during solidification of binary alloys.

So I obtain reynolds number (volScalarField) from the velocity fields of solid and liquid. To obtain the drag coefficient, I need to have an expression like log10(Reynolds). So when I use this, the code compiles. But when I run the simulation I get the following error -

#0 Foam::error:rintStack(Foam::Ostream&) at ??:?
#1 Foam::sigFpe::sigHandler(int) at ??:?
#2 ? in "/lib/x86_64-linux-gnu/libc.so.6"
#3 log10 in "/lib/x86_64-linux-gnu/libm.so.6"
#4 Foam::log10(Foam::dimensioned<double> const&) at ??:?
#5 ? at ??:?
#6 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#7 ? at ??:?
Floating point exception (core dumped)

I am assuming this not the way to calculate logarithmic expressions. Can somebody guide me through this?

Thanks
Akash

[alexeym]

Hi,

(obvious) Are you sure Reynolds field is positive? FPE suggests contrary.

[pakanatiakash]

Its small (order 1e-4) but certainly positive.

[alexeym]

Surely you can set up 1D problem with 10 cells and post output of

Info<< Reynolds << endl

here (just to verify). log10 over field uses standard log10 from cmath, according to "man log10" it raises FPE only when argument is +-0 or <0.

[pakanatiakash]

Rel: 5.67461e-05
Rel: 5.67461e-05
Rel: 0.000116924
Rel: 0.000116924
Rel: 0.000114174
Rel: 0.000114174
Rel: 0.000117549
Rel: 0.000117549
Rel: 0.000113562
Rel: 0.000113562
Rel: 0.000122217
Rel: 0.000122217

The values are correct (with some slight error ofcourse) as I have verified with the analytical model.

[pakanatiakash]

So yea, I got the error. A numerical parameter in my code was the issue. This was setting Reynolds number to zero in some cells. Anyways, thanks for the help

Cheers
Akash

[alexeym]

Hi,

Since your output differs from standard volScalarField output:

dimensions      [0 0 0 0 0 0 0];

internalField   nonuniform List<scalar> 
10
(
...
)
;

boundaryField
{
...
boundaries
...
}

I assume, you are trying to hide something (as I have EXPLICITLY asked for Info<< Reynolds).

Also you can try running debug build to see where exactly (up to line number) you have problem.