[moabdi]

Hi every body
I wrote an UDF to describe the geometry of a RING TORUS.
NOTE:
as you know a torus is a surface of revolution generated by revolving a circle in three-dimensional space about an axis coplanar with the circle. If the axis of revolution does not touch the circle, the surface has a ring shape and is called a Ring Torus.
220px-Torus.png

but I think some thing is wrong about it, because when I try to see preview mesh motion, a small window is opened and show this message: "Resetting" and nothing happens.
the UDF is:

#include "udf.h"
#include "math.h"
#include "sg_udms.h"
#include "sg.h"
#include "stdio.h"
#include "mem.h"
#include "dpm.h"
#include "surf.h"
#define PI 3.14286

DEFINE_GEOM(torus, domain, dt, position)

{

int i, j, n = 360;
real xx[129600], yy[129600], zz[129600];
xx[129600]=0;
yy[129600]=0;
zz[129600]=0;
for (i = 1 ; i <= n ; i++)
{
for (j = 1 ; j <= n ; j++)
{
xx[0]=(50+3*cos (j*PI/180))*cos(i*PI/180);
yy[1]=(50+3*cos (j*PI/180))*sin(i*PI/180);
zz[2]=3*sin(j*PI/180);
}
}
position[0]=xx[129600];
position[1]=yy[129600];
position[2]=zz[129600];
}
DEFINE_CG_MOTION(CUTTING,dt,vel,omega,time,dtime)
{



/* reset velocities */

NV_S(vel, =, 0.0);
NV_S(omega, =, 0.0);

omega[2]=0.3;
}

it's my pleasure if any body could help me.
thanks

[pakk]

for (i = 1 ; i <= n ; i++) 
{ 
for (j = 1 ; j <= n ; j++)
{
xx[0]=(50+3*cos (j*PI/180))*cos(i*PI/180);
yy[1]=(50+3*cos (j*PI/180))*sin(i*PI/180);
zz[2]=3*sin(j*PI/180); 
} 
}

What is this supposed to do? You are redefining xx[0], yy[1] and zz[2] many (n^2) times, without ever using the value in between... It would be equivalent to

xx[0]=(50+3*cos (n*PI/180))*cos(n*PI/180);
yy[1]=(50+3*cos (n*PI/180))*sin(n*PI/180);
zz[2]=3*sin(n*PI/180);

And after that, you never use xx[0], yy[1] nor zz[2] again... I can't follow what you think the parts of your code are doing...

[moabdi]

Hi PAKK

you are right, there are many problems in that UDF, so what's your opinion on how to define a TORUS equation in FLUENT by use of DEFINE_GEOM macro?

[pakk]

I have no opinion, I have never worked with DEFINE_GEOM. But you already wrote a code, so you must have had something in mind when you wrote it...