Coordinate System Restrictions
Recall that for an axisymmetric problem, the axis of rotation must be the axis and the grid must lie on or above the line.
Grid Sensitivity in Swirling and Rotating Flows
In addition to the setup constraint described above, you should be aware of the need for sufficient resolution in your grid when solving flows that include swirl or rotation. Typically, rotating boundary layers may be very thin, and your FLUENT model will require a very fine grid near a rotating wall. In addition, swirling flows will often involve steep gradients in the circumferential velocity (e.g., near the centerline of a free-vortex type flow), and thus require a fine grid for accurate resolution.