[zhaoxinyu]

Hi!
In unsteady DPM model, how to output the position and velocities of particles in a cell at a certain time using UDF?

[Bernhard]

I once obtained this from Fluent support desk. Good luck

/********************************************************************/ 
/* */
/* Hook on the DPM panel under DPM Scalar Update */
/* */
/********************************************************************/

#include "udf.h"
#include "dpm.h"

DEFINE_DPM_SCALAR_UPDATE(track_dpm_particles,c,t,initialize,p)
{
if (RP_Get_Boolean("dpm/unsteady-tracking?"))
{

if (initialize)
{

float time = RP_Get_Real("flow-time");
float x = p->state.pos[0];
float y = p->state.pos[1];
float u = p->state.V[0];
float v = p->state.V[1];
#if RP_3D
float z = p->state.pos[2];
float w = p->state.V[2];
#endif

FILE *fd;
int id = p->part_id;
char whoru[80];
sprintf(whoru,"dpm_positions%f.out",time);
fd = fopen(whoru, "a");
#if RP_3D
fprintf(fd, "%i %f %e %e %e %e %e %e %e %e %e \n", id, time, x, y, z, u, v, w, P_T(p), P_MASS(p), P_RHO(p));
#else
fprintf(fd, "%i %f %e %e %e %e %e %e %e \n", id, time, x, y, u, v, P_T(p), P_MASS(p), P_RHO(p));
#endif
fclose(fd);

}
}

else
{
float time = RP_Get_Real("flow-time");
float x = p->state.pos[0];
float y = p->state.pos[1];
float u = p->state.V[0];
float v = p->state.V[1];
#if RP_3D
float z = p->state.pos[2];
float w = p->state.V[2];
#endif

FILE *fd;
int id = p->part_id;
char whoru[80];
sprintf(whoru,"dpm_positions%f.out",time);
fd = fopen(whoru, "a");
#if RP_3D
fprintf(fd, "%i %f %e %e %e %e %e %e %e %e %e \n", id, time, x, y, z, u, v, w, P_T(p), P_MASS(p), P_RHO(p));
#else
fprintf(fd, "%i %f %e %e %e %e %e %e %e \n", id, time, x, y, u, v, P_T(p), P_MASS(p), P_RHO(p));
#endif
fclose(fd);
}

}

[zhaoxinyu]

Originally Posted by Bernhard

I once obtained this from Fluent support desk. Good luck

/********************************************************************/ 
/* */
/* Hook on the DPM panel under DPM Scalar Update */
/* */
/********************************************************************/
 
#include "udf.h"
#include "dpm.h"
 
DEFINE_DPM_SCALAR_UPDATE(track_dpm_particles,c,t,initialize,p)
{
if (RP_Get_Boolean("dpm/unsteady-tracking?"))
{
 
if (initialize)
{
 
float time = RP_Get_Real("flow-time");
float x = p->state.pos[0];
float y = p->state.pos[1];
float u = p->state.V[0];
float v = p->state.V[1];
#if RP_3D
float z = p->state.pos[2];
float w = p->state.V[2];
#endif
 
FILE *fd;
int id = p->part_id;
char whoru[80];
sprintf(whoru,"dpm_positions%f.out",time);
fd = fopen(whoru, "a");
#if RP_3D
fprintf(fd, "%i %f %e %e %e %e %e %e %e %e %e \n", id, time, x, y, z, u, v, w, P_T(p), P_MASS(p), P_RHO(p));
#else
fprintf(fd, "%i %f %e %e %e %e %e %e %e \n", id, time, x, y, u, v, P_T(p), P_MASS(p), P_RHO(p));
#endif
fclose(fd);
 
}
}
 
else
{
float time = RP_Get_Real("flow-time");
float x = p->state.pos[0];
float y = p->state.pos[1];
float u = p->state.V[0];
float v = p->state.V[1];
#if RP_3D
float z = p->state.pos[2];
float w = p->state.V[2];
#endif
 
FILE *fd;
int id = p->part_id;
char whoru[80];
sprintf(whoru,"dpm_positions%f.out",time);
fd = fopen(whoru, "a");
#if RP_3D
fprintf(fd, "%i %f %e %e %e %e %e %e %e %e %e \n", id, time, x, y, z, u, v, w, P_T(p), P_MASS(p), P_RHO(p));
#else
fprintf(fd, "%i %f %e %e %e %e %e %e %e \n", id, time, x, y, u, v, P_T(p), P_MASS(p), P_RHO(p));
#endif
fclose(fd);
}
 
}

Thanks for you help!

[orland]

when I tried to use that code, all the particle id's get the value zero
has this also happened to you?

[arctan]

The code works fine except that it writes duplicated data for me, the positions and velocities are repeated 4 times in the .out file, why? and how to fix it?

[pakk]

Are you working in parallel mode with four processes? In that case, the reason that you get four lines is that this code is not meant for parallel computing.

This can be fixed by parallelizing the code (putting the correct macro's in the right position, see Fluent manual for more info). But if you are not familiar with this, it might be better to just ignore the extra output you get.

[arctan]

The thing is that I'm working in serial, so it's weird that I'm getting four lines. My computer has four cores though, I'm not sure if it has anything to do with four cores.