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-   -   same velocity in inlets (http://www.cfd-online.com/Forums/fluent/121465-same-velocity-inlets.html)

rayan24 July 29, 2013 11:43

same velocity in inlets
 
I want to impose by UDF a same velocity profile in 3 inlets, but i don't get same velocity in the 3 inlets apparently i impose my profile in function of the distance r!!

how can i impose my velocity profile in the "surface" of inlet to get samevelocity please??

my udf is :

HTML Code:

#include "udf.h"
DEFINE_PROFILE(w_velocity_inlet,t,i)
{
real x[ND_ND]=3; /* this will hold the position vector */
real r;
face_t f;
begin_f_loop(f,t)
{
F_CENTROID(x,f,t);
r = x[0];
F_PROFILE(f,t,i) = -((0.0431*pow(r,3))-(0.3857*pow(r,2))+(0.3129*r)+8.8045);
}
end_f_loop(f,t)

thanks

Amir July 29, 2013 15:58

Dear Rayan,

Your profile is a function of x-coordinate, so you will get different results if the elements of these inlets have different x positions! Did you expect something else?!

Bests,

rayan24 July 29, 2013 17:14

Tank you Amir for your replay,

My 3 inlets are aligned in the XY plane, so the Inlet 1 ranges between x = [1, 4.5], inlet 2 is between x = [5, 7.5] and the inlet 3 is between x = [5, 7.5], so I can't get to impose my velocity profile in each inlet!

Do you have an idea please?

Amir July 30, 2013 03:41

Quote:

Originally Posted by rayan24 (Post 442676)
Tank you Amir for your replay,

My 3 inlets are aligned in the XY plane, so the Inlet 1 ranges between x = [1, 4.5], inlet 2 is between x = [5, 7.5] and the inlet 3 is between x = [5, 7.5], so I can't get to impose my velocity profile in each inlet!

Do you have an idea please?

Hi,

There are lots of options. You can either use if-clauses to switch between different thread IDs or simply use 3 UDFs.

Bests,

rayan24 July 30, 2013 03:46

Thanks for your response :p

Mohammad80 November 19, 2013 07:41

Udf
 
Hello Amir,
Could you please help me?
I have a problem writing a UDF for my 2D-geometry.
I hope you have time to contact me at my E.mail address:
mas20001920@yahoo.com

Best regards.


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