[vishnuambali@gmail.com]

Following is my UDF for imparting a particular velocity along the cylinder surface.Though the UDF got compiled but the mathematical functions and (execute at end) is not executed...

What might be the reason...Pls help

#include <udf.h>
#include <math.h>
static real k;
DEFINE_EXECUTE_AT_END(execute_at_end)
{
real time;
time = RP_Get_Real("flow-time");
if(time>190)
{
k=10;
}
else
{
k=0;
}
}
DEFINE_PROFILE(cylinder_x_velocity, t, i) /* cylinder x velocity = name of the x velocity */
{
real y,x; /* variable declarations */
real z[ND_ND];
face_t f;

begin_f_loop(f, t) /* thread = given boundary zone, defined automatically when the UDF is hooked to cylinder boundary, the macro begin_f_loop is applied to all the cell faces*/
{
F_CENTROID(z,f,t); /* the coordinates of the face centroid accessed by F_CENTROID */
x = z[0];
y = z[1]; /* this will hold the position vector */
if(((x*x)+(y*y)==.25)&&(y>=0))
{
F_PROFILE(f,t,i)=k*y/sqrt((x*x)+(y*y)); /* return velocity is assigned through F_PROFILE */
}
if(((x*x)+(y*y)==.25)&&(y<0))
{
F_PROFILE(f,t,i)=-k*y/sqrt((x*x)+(y*y)); /* return velocity is assigned through F_PROFILE */
}
}
end_f_loop(f, t)
}
DEFINE_PROFILE(cylinder_y_velocity, t, i) /* cylinder y velocity = name of the y velocity */
{
real y,x; /* variable declarations */
real z[ND_ND];
face_t f;
{
begin_f_loop(f, t) /* thread = given boundary zone, defined automatically when the UDF is hooked to cylinder boundary, the macro begin_f_loop is applied to all the cell faces*/
{
F_CENTROID(z,f,t); /* the coordinates of the face centroid accessed by F_CENTROID */
x = z[0];
y = z[1]; /* this will hold the position vector */
if(((x*x)+(y*y)==.25)&&(x>=0))
{
F_PROFILE(f,t,i)=k*x/sqrt((x*x)+(y*y)); /* return velocity is assigned through F_PROFILE */
}
if(((x*x)+(y*y)==.25)&&(x<0))
{
F_PROFILE(f,t,i)=-k*x/sqrt((x*x)+(y*y)); /* return velocity is assigned through F_PROFILE */
}
}
end_f_loop(f, t)
}
}

[ksingh]

Hi!!
You can write to me on ksingh[at]tserc[dot]in