UDF for 3D circular inlet
 

I had tried with the below UDF progamme but it cannot produce a parabolic profile at the 3D inlet. So i need some advise on my programme. thanx

#include "udf.h"

DEFINE_PROFILE(inlet_y_velocity, thread, position) { real y[ND_ND]; /* this will hold the position vector */ real x, z, r; face_t f; r=x=z;

begin_f_loop(f, thread)

{

F_CENTROID(y,f,thread);

x = y[1];

z = y[2];

r = y[3];

F_PROFILE(f, thread, position) = .07667 - r*r/(.0075*.0075)*.07667;

} end_f_loop(f, thread) }

Re: UDF for 3D circular inlet
 

y is an array which store the centroid coordination(x0,y0,z0),that is,y[0]=x0,y[1]=y0,y[2]=z0, so if your inlet face is parallel to x diretion, for example x=100mm , and you want to use y0 as the r value, you should write the program as:

r=y[1]; if you use r=y[3], maybe you will not get any value for r. hope useful for you.