Multiphase FSI validation cases

Hi @Stan,

unfortunately, there is no tutorial for multiphase FSI yet (contributions welcome). However, other people have already tried, and your question sounds very similar to this one: OpenFOAM adapter for InterFoam: Density in Incompressible flow In principle, we use (and need) the density from preciceDict in incompressible cases. Since interFoam is a bit special, it is treated as a compressible solver:

See also:

Writing up some documentation (even just here) would be very useful.

PS: The category “Official adapters and tutorials” seems more fitting here than “non-preCICE”, as this really seems to be related to the OpenFOAM adapter implementation.