Parabolic UDF velocity check in Fluent 17.1
 

Dear Members,

I am a new user to the FLUENT module and have just started to use user-defined function in FLUENT17.1
I wrote a user-defined function for a parabolic flow profile in 3d cylinder which is as follows:

#include "udf.h"
DEFINE_PROFILE(inlet_vel_parabolic, thread, index)
{
/******** user input *********/
real vel_avg=0.1;
real radius=0.0035;

/******** user input *********/
face_t face;
real xc[3];
begin_f_loop(face, thread)
{

F_CENTROID(xc,face,thread);
F_PROFILE(face, thread, index) = 2.*vel_avg*(1-((xc[1]*xc[1]+xc[2]*xc[2])/(radius*radius)));
}
end_f_loop(face, thread)
}

My simulation does not have a reverse flow during the simulation but however while checking the contour after simulation, it has a weird profile.The required profile at the inlet appears at the outlet and vice-versa.
This problem has only been encountered in the newer version of Fluent 17.1 and not in the older version.

Kindly guide me through this issue.