Forum Moderator

Check the cell zone reference settings. The idea of the tangential & axial velocity is for cyclones where we expect a constant tangential velocity with radius. 

Not clear on here but you may want to read up on (precessing) vortex cores - Nick Syred did a lot of the earlier work. Also have a look at the radial pressure distribution option on the pressure outlet. 

We can stop the backflow numerically, but it's not going to mean you're not modelling reality. It's also why one of the last lines in the Accuracy lecture is roughly "understand what you're modelling". In this case, that's not easy.