Ansys Employee

I think the solver will deal with the buoyancy effects automatically - there's a reason we add mass to the 6DOF model! 

The best option for cell type tends to depend on what you want to know, and how you're modelling it. One approach that does work well is to drop the object with a fixed mesh around it and remesh further away: that means there's no remeshing around the object of interest and you can use inflation.