Solution singularity (Benchmark problem: Sucking Interface Problem)

[Bumble-7]

Dear Authors, I downloaded the recent version of code and tried to run the benchmark cases. The 1D sucking interface problem throws the error "DILUPBiCGStab: Solving for Ux: solution singularity". I am attaching the setup files below.

https://github.com/Bumble-7/Benchmark_simulations

Thank you

[Bumble-7]

Is it possible for someone to comment on this issue?

[HenningScheufler]

Have you tried the smoothSolver instead of PBiCGStab?

[Bumble-7]

Thanks for the response. I haven't actually, let me try. I just executed the benchmark case by running Allrun file. So it ran considering the parameters which are already present in the files.

[Bumble-7]

The problem is solved using the smoothSolver. Thank you for the clarification. I have an additional doubt regarding the initAlphaFieldDict. Even though the alpha.water is set in the setFieldsDict file explicitly, is it necessary to run the initAlphaFieldDict? I see that if I skip initAlphaFieldDict, the interface actually doesn't move. There is also a gradual variation of the alpha if I use it. Will the solver won't work if we have a discontinuous alpha field?

Kindly request you to shed light on the same. Thank you

[HenningScheufler]

The phasechange mass flow needs a surface area and the interface is only calculated in the cells with a value smaller 1 or larger zero. So if you use setFields. It will not find an interface so nothing happens

[Bumble-7]

Ok, I understand now. Thanks again for your time.