Dynamic Meshing for fluent multiphase
 

I need to do good dynamic meshing. What will be best meshing scheme for capturing the dynamic lift of Semi-planing hull during fast speeds. And how much cells should be there. Computational power is 32 GB RAM, 12 Cores. Processor i7.

6dof
 

It depends on many other things, computational power being least important. You need to look at the size of the hull, the resolution required, Froude number, etc. because these will define the average thickness of the free surface.

With 32 GB RAM, you can go up to 4-6 million cells, but that, most likely, won't be required. Do not use all 12 cores because there is not enough RAM. Ensure that Hyper-Threading is disabled because that does not help. Use a maximum of 4-6 cores. You may end of hanging the simulation with more cores due to RAM. Speed will depend on speed of RAM as well as that of processor.

For stability, I'd recommend using coarser mesh in the beginning and tetrahedral mesh only around the free surface where mesh deforming has to take place. Another alternative is to use overset mesh. You will be able to use larger time-step and finer mesh with overset.