Cylindrical Boundary Conditions
 

I am wanting to use an inlet BC at the end of a cylinder that will cause a rotational flow field along the cylindrical wall. Ideally the inlet flow will be tangential to the outer wall all around the cylinder, requiring a BC that has a changing inlet flow vector.

So the question is...

Is there a way to specify flow direction based on a reference point/position in cylindrical coordinates?

Thanks, Nick

P.s. - The only reason I am not too keen on using a rotating frame of reference is that I want to see where the rotational flow field will break down.