[SeoYeonKim]

Hello, I am new to FLUENT and currently working on fluid simulation with the model consists of multiple inlets and outlets.

I'm trying to apply parabolic velocity profile of a laminar flow using the below UDF code and keep failing it.
-----------------------------------------------------------------------
#include "udf.h"
#include <math.h>


DEFINE_PROFILE(parabolic_flow,t,i) /* t = therad, i = position */
{
real x[3];
real r, Umax;
real Umean = 150;
real R =0.3;
face_t f;

Umax = 2 * Umean;
r = sqrt(pow(x[0],2)+pow(x[1],2)+pow(x[2],2));

begin_f_loop(f,t)
{
F_CENTROID(x,f,t);
F_PROFILE(f,t,i) = Umax * (1 - (pow(r,2)/pow(R,2)));
}
end_f_loop(f,t)
}
--------------------------------------------------------------------------
please look through the code and any help will be appreciated.

Thank you in advance

[AlexanderZ]

r = sqrt(pow(x[0],2)+pow(x[1],2)+pow(x[2],2));

should be inside the loop

[SeoYeonKim]

Thank you for the reply

Now I'm testing the code with a simple cylinder structure but keep getting the velocity contour as below, literally similar to the flat velocity profile rather than parabolic velocity profile.. (I've used low enough velocity to apply laminar flow )

I believe if I apply parabolic velocity profile, contour inside the cylinder should be red in the middle and gradually become blue as it reaches the boundary layer unlike the figure below.

would this be the problem resulted due to the code or any setting that I'm using for the simulation?