[Gaetano]

Hi all.

This is my first post here, so I'm going to introduce myself: my name's Gaetano and I'm doing a PhD in Chemical Engineering in Naples (Italy).

I've been lurking those forums for at least 6 months and I found answers to almost all my questions. This one, however, seems to be a bit more tricky.

I'm trying to have interFoam working with one of the two phases being a perfect fluid, i.e. having zero density and viscosity (I'd like to simply put "0" in the dictionary transportProperties). In doing so, I need to avoid all the division by density, if any. I found some in class twoPhasesMixture and I created a new class twoPhaseMixturePerfect with a little (tricky) workaround in it. When I tried to solve the damBreack tutorial with my interPerfectFoam I found this error at the very first step:

------------------------------------------------------------------------
Starting time loop

Courant Number mean: 0 max: 0
Interface Courant Number mean: 0 max: 0
deltaT = 0.00119048
Time = 0.00119048

MULES: Solving for alpha1
Phase-1 volume fraction = 0.130194 Min(alpha1) = 0 Max(alpha1) = 1
MULES: Solving for alpha1
Phase-1 volume fraction = 0.130194 Min(alpha1) = 0 Max(alpha1) = 1
#0 Foam::error:rintStack(Foam::Ostream&) in "/share/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#1 Foam::sigFpe::sigHandler(int) in "/share/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#2 __restore_rt at sigaction.c:0
#3 Foam::divide(Foam::Field<double>&, double const&, Foam::UList<double> const&) in "/share/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#4 main in "/local/home/iitcrib3/GaetanoDM/damBreak/interPerfectFoam"
#5 __libc_start_main in "/lib64/libc.so.6"
#6 Foam::regIOobject::writeObject(Foam::IOstream::str eamFormat, Foam::IOstream::versionNumber, Foam::IOstream::compressionType) const in "/local/home/iitcrib3/GaetanoDM/damBreak/interPerfectFoam"
Floating point exception
------------------------------------------------------------------------

It seems that there is a problem with a division (see #3 above) in the p_rgh solver (as the next step should be "DICPCG: Solving for p_rgh ..."), but my insight into the problem ends here.

So, here's my question: what does the above error mean? Is there any division with a density in the denominator anywhere in interFoam?

But, besides the answers, I'm also looking for advice from expert foamers like many here: is there any chance that my attempt to "hack" interFoam could fit in its "architecture"? I mean: does the algorithm require a division by a density? I'd like to modify only the "shell" and not the "core" of interFoam (sorry for the poor analogy: I can't figure out any better way to make my point).

Thanks in advance,
Gaetano