[Mohammed Attya]

Hi, I am solving a problem for a 3D duct (rectangular cross-section)
I used this UDF for inlet velocity profile for turbulent flow
mean velocity = 1 m/s
cross section = 40 * 40 mm in (Y & Z)

#include "udf.h"
#define H 0.04 /*meter*/
#define UMEAN 1. 

DEFINE_PROFILE(inlet_profile,t,i)
{
real x[ND_ND]; 
real y;
face_t f;
begin_f_loop(f,t)
{
F_CENTROID(x,f,t);
y = x[1];
if (y > (H/2))
	F_PROFILE(f, t, position) = UMEAN * 1.224 * pow((H-y)/(H/2.),(1./7.));
else
	F_PROFILE(f, t, position) = UMEAN * 1.224 * pow(y/(H/2.),(1./7.));
}
end_f_loop(f,t)
}

the problem is the velocity profile is uniform in Z-direction (U1 = U2 = U3)
U1 => U at Z = 0
U2 => U at Z = 20
U3 => U at Z = 40