[ashkan39t323]

Hi guys,
How can i create udf for a wind tunnel simulation in architecture using LES model. The parameters are:
H=320m (wind tunnel height in y direction)
h(building)=200m (building height in the wind tunnel (y direction))

Wind Profile (x_velocity) calculation is:

v2=v1 * (ln[h2/0.8]) / (ln[h1/0.8))
The reference wind speed v1 is measured at height h1. v2 is the wind speed at height h2.

Considering v1=1m/s in h1=1m
what is the problem of this udf.
Tnx alot

#include "udf.h"

DEFINE_PROFILE(inlet_x_velocity, thread, position)
{
real x[ND_ND];
real y;
face_t f;

begin_f_loop(f, thread)
{
F_CENTROID(x,f,thread);
y = x[1];
F_PROFILE(f, thread, position) = (log10(y/0.8))/(0.223143);
}
end_f_loop(f, thread)
}

[pakk]

Originally Posted by ashkan39t323

what is the problem of this udf.

It would be better if you would tell the problem you have with this UDF. So that we don't have to guess what you are talking about. Compile error? Run error? Unexpected results? I am sure you have tried this UDF, tell us what came out of it.

But even without that information, I guess some unexpected results can be caused by the fact that you don't tell Fluent what x should be. For me it is clear that you mean x to be the position of cell f, but the compiler cannot guess that.