[ppx]

Dear All,

I'm doing a simulation about a moving light beam and i really need some help.
In my simulation the light beam should move spirally. I want to use a UDF to define the movement of the light beam. I have found a code about a Laser beam moving along y. I tried to change the code to define the movement along x and y but it didn't work. Does anyone know how can i define the x path also so that the light beam can move spirally?
Thank you all in advance.


Here the udf:

#include "udf.h"

DEFINE_PROFILE(laser_beam,t,i)
{
real y[ND_ND];
real Y;
real y_0=-0.008; //starting point
real v=0.003; //velocity of the laser beam
real b=0.018; //width of the laser beam
real I_0=10000000000; //Intensity
real time=RP_Get_Real("flow-time");
face_t f;
begin_f_loop(f,t)
{
F_CENTROID(y,f,t);
Y=y[1];
if(Y>=y_0+time*v-b/2 && Y<=y_0+time*v+b/2) // moving along y
F_PROFILE(f,t,i) = I_0;
else
F_PROFILE(f,t,i) = 0;
}
end_f_loop(f,t);
}