udf - coordinate problem
 

Hi there,
I'm trying to write an UDF which calculates slip at journal bearing wall. I am using the UDF I found from this forum: goo.gl/aE54Jz but it doesn’t work on journal bearing (probably because journal bearing use cylindrical coordinate system).


Do anybody know how to convert the cartesian velocity field (ux, uy, uz) into a cylindrical velocity field (u_radial, u_tangential, u_axial) and how to derivate it (du dr, du dθ, du dz)?


I am looking forward for your respond. Thank you.


Best regards
Hilmy M. Fauzan