Parralel/Rotational velocity boundary condition on Wedge mesh
 

Hello all, I've made a simple wedge type mesh with ID and OD. The ID is a shaft while the OD is the casing with a gap between the two simulating wear of the sealant.(supposed to be modeled as an annular) The shaft rotates at 371.75 rads/sec which makes the surface velocity 10.5 m/s. Flow is pressure induced, with a pressure gradient "fixedValue" on the inlet and outlet boundary conditions. Velocity BC's are "zeroGradient".

Problem 1: I'm confused on how to switch to cylindrical coordinates, if at all possible.

Problem 2: I've made the model using pimpleDyMFoam and it's been running for 2 days now and hasn't converged. It's close... i think, but I want to test several pressure gradients. A rotating mesh seems computationally extensive.

I'm hoping for a simple solution and sure there is one.
I'm running OF 2.3 on Ubuntu 14.04 (Just reinstalled). i understand some older versions of OpenFoam have more BC's so if it is install an older version of OpnFoam, then so be it.

Thanks in advance