When parameter artTransform is on, the velocity components are of axial radial and tangential meaning. Otherwise, the velocity components are always Cartesian.
The inlet patch is virtually divided in to number of intervals. When parameter h is prescribed (with e.g. five height levels), the inlet patch is virtually divided into six intervals. Into each interval is prescribed corresponding value (linear interpolation is employed here).
Figure: The definition of axial, radial and tangential velocity components.
Any design of a real geometry contains complex details such as solids, screws, mounting joints, sealings, nuts, etc. To simulate a flow we need to have a clear geometry describing a flow path only. See figure below.
Solid geometry
Flow path geometry
INPUT RULE 1: Having a clear geometry describing the flow path only.