UDF parbolic inlet velocity profile for 3D channel flow.
 

inlet is y=1cm and z=17cm, for 2D case i am using

#include "udf.h"
DEFINE_PROFILE(inlet_x_velocity, thread, position)
{
real x[ND_ND]; /* this will hold the position vector */
real y;
face_t f;
begin_f_loop(f, thread)
{
F_CENTROID(x,f,thread);
y = x[1];
F_PROFILE(f, thread, position) = 0.4382 - y*y/(0.005*0.005)*0.4382;
}
end_f_loop(f, thread)
}

what modification required to change this into 3D parabolic velocity profile.

thanks