I'm trying to model 2D axisymmetric flow between two disks with a parabolic Heat flux profil at the wall...But my UDF doesn't work...I need Help!!!

#include"udf.h"

DEFINE_PROFILE(flux,t,position) {

real x[ND_ND];

real y;

face_t f;

begin_f_loop(f,t)

{

F_CENTROID(x,f,t);

y = x[1];

F_PROFILE(f, t, position)=10.8456295*(y*y);

}

end_f_loop (f,t) Message("flux: %f\n", F_PROFILE(f, t, position)); }

What is the meaning of "doesn't work"? Interpretation failure? Calculation failure or sth?

Besides I cannot get the point of axisymmetric flow between two disks. Axis or symmetry?