[wanghaojie]

Hi all,
I wrote a UDF to record transient data but I usually get lots of zero for one time step and also two non-zero data for a single step, does anyone know whats wrong in my code?
Thanks
I try to calculate the bi-directional flow thru a opening and record the flow rate.


#include "udf.h"
#define ID1 10036 /*Window ID*/
#define ID2 10028 /*Horizontal Plane ID*/
#define ID3 10040 /*Horizontal Plane Inside ID*/
#define ID4 10029 /*Vertical Plane ID*/
#define ID5 10042 /*Vertical Plane Inside ID*/
#define ID6 2 /*Building ID*/
#define Vel 3
#define Angle 90
#define Alfa 1.0
#define Gama 0.15
#define rho 1.225

FILE *fp;
DEFINE_EXECUTE_AT_END(SaveData)
{
Domain *d;
face_t f;
real A[2];
real x[ND_ND],z;
Thread *t,*t0,*t1;
real incid;
real P=0,Vol=0,VolTotal=0,u=0,v=0,v_door=0,VentRate=0,t ime=0;
cell_t c, c0, c1;
/*Ventilation Rate*/
fp = fopen("VentRate.csv","a+");
d = Get_Domain(1);
t = Lookup_Thread (d, ID1);
begin_f_loop(f, t)
{
F_AREA(A,f,t);
c0 = F_C0(f,t);
t0 = THREAD_T0(t);
c1 = F_C1(f,t); /* Get cell on other side of face */
t1 = THREAD_T1(t);
v_door= 0.5*(C_V(c0,t0)+C_V(c1,t1));/*Average the velocity before and after the door)*/
VentRate=0.5*fabs(A[1]*v_door)+VentRate;
}
end_f_loop(f, t)
time=CURRENT_TIME;
fprintf (fp, "%g,%g\n",time, VentRate);
fclose(fp);

and so on....

and the results i get is like:
344.35 0
344.35 0
344.35 0
344.35 0
344.35 0
344.35 0
344.35 0.209489
344.35 0
344.35 0.281943
344.38 0
344.38 0
344.38 0.198774
344.38 0
344.38 0.27797
344.38 0
344.38 0
344.38 0
344.38 0
344.41 0
344.41 0
344.41 0
344.41 0
344.41 0.271995
344.41 0
344.41 0.187409

[wanghaojie]

does anyone have this kind of problem before

[wanghaojie]

I see even if i use printf in the console, it still has several data at one time step....

[wanghaojie]

I finally figure it out. Its because i use parallel fluent and each cpu will give a result