problem with solving pipe flow in rotating reference frame
 

Hi all!

I am using a code developed by a Professor of my University (caffa3d), for simulating the flow through an axial pump.

I am working in a rotating reference frame, and I have added Coriolis and centrifugal accelerations, and all the boundary conditions are well applied (at least I think so!)

When I look the tangential component of the relative velocity inside the pipe far away upstream from the pump, it doesn't look like it should. It should have a solid body rotation (because the absolute velocity should be purely axial), but instead it rotates with less magnitude.

I have tested a simpler case of the flow inside a circular pipe (without pump) with several boundary conditions at outlet (zero gradient, zero total derivative, constant pressure) but all of them give the same result.

Anyone have an idea why this occurs?

Thanks!