Gradient in UDF
 

Hello, everyone. I would like to write a UDF which has the gradients of velocity. I apply axis-symmetry solver in order to get the solution of a pipe (similar to the example 1 in FLUENT document :laminar flow in pipe). Now I am confused that if I could get the right gradient of velocity in x direction when I use C_U_G. Should I consider the difference of Polar Coordinates amd Cartesian Coordinates? Thank you in advance.