> Do you volunteer to write and maintain that code?

Yes. Since that would basically mean extending the incompressible twophase simulator to the compressible case (which should not be that much work assuming that the incompressible simulator works fine which I have not tested.)

also, if it is just about the capability to run twophase cases, I volunteer to update the initialization routines for the threephase simulator...

> We have code in place that's specifically intended to handle OW, OG, and OWG problems

I know, but the problem is that currently the two-phase and the three-phase code for the simulators are the same which leads to a nasty salad of ifs in some places...