Small world, I used to work for an industrial CFD company, and one of my tasks was estimating the computational effort required for a given simulation (which depended on the specific characteristics of our turbulence model). I was mostly doing compressible work, too, so my knowledge of hydrodynamic models used in cinema is not super detailed. I do know, however, that most cinema software uses particle based simulation for incompressible flow, which really is not a terrible approximation, but it probably would not be suitable for the kind of work you are doing!