Cavitation has nothing special other than multi-phase flow. And implementing a VOF method is definitely in our roadmap. You can currently simulate it without cavitation to get a feeling of the unsteady flow solution, or wait for us to implement VOF.
Then you should is a different solver that fills your needs.
WaterLily is an incompressible flow solver that works in non-dimensional units (assuming constant unit density). So you can change the viscosity of the fluid by modifying the Reynolds number (with set a set characteristic velocity and length scale).
