[Help Please], Trouble Using UDF to Import Velocity Data -- But All Zeros :(
 

Hello, Friends

I know that I bothered you guys so much but really need help from you guys. I am using Fluent UDF to import velocity from local data files. But the output are always zero, I tested the C program by local c compiler, it works great as what I expected. Please, please take a look at my UDF and let me know what you believe are wrong, thanks a lot!

#include "udf.h"
#include "mem.h"
#include <stdio.h>

int Nz = 512;
int ts, n;
char buffer[50];
real u, v, w;

DEFINE_PROFILE(x_velocity, t, i){
FILE *fid;
face_t f;
/************************* Construct file names here **************************/
ts = N_TIME;
n = sprintf(buffer, "Uf_%i.dat", ts % Nz);
Message("Importing x-velocity from %s...", buffer);
fid = fopen(buffer, "r");
begin_f_loop(f, t){
fscanf(fid, "%f %f %f\n", &u, &v, &w);<=== u, v, w read from here are always zeros :(
/* printf("u = %f, u = %f, u = %f\n", u, v, w);*/
F_PROFILE(f,t,i) = u;
}
end_f_loop(f,t)
fclose(fid);
Message("Done\n");
}

The data files look like this below

7.241065 -8.430264 85.50916
-9.164535 -1.508738 82.77167
10.84698 -2.585959 90.85329
-3.974935 -2.802197 92.33000
... ...

I also want to know how to read a big data file and assigne velocity to the boundary.

for example, save the unsteady outflow boudary velocity data, and use it as inlet velocity in another simulation.