HELLO TO EVERY ONE, CAN YOU HELP ME AND INFORM ME ABOUT udf . I WANT TO DEFINE A VELOCITY DISTRIBUTION AT INLET BUT I JUST KNOW THE MAGNITUDE OF VELOCITY AT CERTAIN POINTS, AND I HAVE NO PROFILE AS AN EQUATION. DOES ANY ONE KNOW HOW I CAN DO THAT.

Plot the discrete velocities at the specified points using some software like e.g. excel. You can get the best fit profile/curve for the curve. Then after getting the equation of the velocity profile, you can use UDF (macros)to define the profile and run Fluent(see the UDF manual..Sec 1.7 A Step-by-Step UDF Example). Else you can write the velocity and its x,y,z locations in fluent format. This is easy too. See the fluent manuals (User Guide, section 3.3 Reading and Writing Case and Data Files)for that.

Good Luck