UDF for rotating wall
 

Hello. I'm trying to program a UDF to simulate the rotation of a boundary in my Fluent model. The geometry I'm trying to create is an inverted cone (cone apex at the bottom, cone base at the top) rotating above a flat plate. Fluid flows within the gap between the cone surface and the plate. The cone rotates at an angular velocity that is time-dependent and periodic but that cannot be expressed as or approximated by a simple function (like a polynomial, exponential, logarithmic, etc). I was thinking about decomposing the function into a FFT and then using an inverse FFT in a UDF in order to extract the value at the current time. I really have no clue about how to do that. If you have any other suggestion or if you think you might be able to help, please let me know. Thank you!