Reply To: Multiphase MRF Simulation for Achimedes Screw Pump

[Rob]

That's fine, and as it's related you're right to continue in the same thread. 

Tets are fine, and support VOF and adaption. 

You do need to review the mesh though. Look at the jump in cell size on the "high" side of the screw to the surrounding mesh: for non conformals the maximum jump does matter, I can't remember the ratio but 1.4 vaguely rings a bell. 

Sliding mesh is where a block/volume moves (typically rotates) and no remeshing takes place. It's computationally fairly cheap, and means you can't get a worse mesh during the model run. Dynamic mesh means the solver will throw away the volume mesh every few time steps and remesh. Very good for moving objects (deforming bodies or things falling off aeroplanes) but computationally demanding. I'd favour sliding mesh here.

You may want to have a look at mesh decompostion. The screw probably wants a tet mesh, but I'm less sure you need tets in the main chambers. Note, I learnt to mesh when we only had hex elements and body fit was only just being introduced (block hex) so I'm used to seeing how to split domains up: I'd probably use a poly mesh, but could hex it all if I really wanted to. It's a skill we don't use as much at the moment, but one that's worth developing efficient (but time consuming) meshing has it's place in the modern CFD world.