[zyfantastic]

Hi all,
I am trying to get the particle position in domain in a transient flow by UDF. I tried to use DEFINE_EXECUTE_AT_END so that I can get the position every time step. my code is as follows:
DEFINE_EXECUTE_AT_END(gpif)
{
Injection *Ilist;
Injection *I;
Particle *p;
Ilist = Get_dpm_injections();
FILE *fid1;
fid1 = fopen("particleposition.txt","w");
loop(I,Ilist)
{
loop(p, I->p_init)
{
fprintf(fid1, "%f %f %f %f %f %f %f %"int64_fmt"\n",P_POS(p)[0],P_POS(p)[1],P_POS(p)[2],P_VEL(p)[0],P_VEL(p)[1],P_VEL(p)[2],P_TIME(p),p->part_id);
}
}
fclose(fid1);
}
I can only get the initialization position of the particles.
if I change Particle *p to Tracked_Particle *p, the fluent just crashed.
Can someone help me to solve the problem please?
Thanks in advance.
zyFan

[gearboy]

Your code seems only prints the position of particles at injections. They will not be tracked at each iteration end. So error occurs. I suggest you use DPM macros, such as DEFINE_DPM_SCALAR_UPDATE(name,c,t,initialize,p), where p is just the Tracked_Particle * type given by Fluent.

Originally Posted by zyfantastic

Hi all,
I am trying to get the particle position in domain in a transient flow by UDF. I tried to use DEFINE_EXECUTE_AT_END so that I can get the position every time step. my code is as follows:
DEFINE_EXECUTE_AT_END(gpif)
{
Injection *Ilist;
Injection *I;
Particle *p;
Ilist = Get_dpm_injections();
FILE *fid1;
fid1 = fopen("particleposition.txt","w");
loop(I,Ilist)
{
loop(p, I->p_init)
{
fprintf(fid1, "%f %f %f %f %f %f %f %"int64_fmt"\n",P_POS(p)[0],P_POS(p)[1],P_POS(p)[2],P_VEL(p)[0],P_VEL(p)[1],P_VEL(p)[2],P_TIME(p),p->part_id);
}
}
fclose(fid1);
}
I can only get the initialization position of the particles.
if I change Particle *p to Tracked_Particle *p, the fluent just crashed.
Can someone help me to solve the problem please?
Thanks in advance.
zyFan

[zyfantastic]

Hi gearboy,

Thanks for your answer, I have tries the DEFINE_DPM_SCALAR_UPDATE(name,c,t,initialize,p). But it exported too many particle data information as the macros is called every time a particle position is update. If I set the condition if (P_TIME(p) == CURRENT_TIME), the code is as follows:

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

DEFINE_DPM_SCALAR_UPDATE(gpif,c,t,initialize,p)
{
int n;
n = N_TIME;
char filename[50];
real current_time = CURRENT_TIME;
snprintf(filename,50,"particleposition_%d.txt",n);
FILE *fid1;
fid1 = fopen(filename,"a");
if (P_TIME(p) == CURRENT_TIME)
{
fprintf(fid1, "%f %f %f %f %f %f %f %"int64_fmt"\n",P_POS(p)[0],P_POS(p)[1],P_POS(p)[2],P_VEL(p)[0],P_VEL(p)[1],P_VEL(p)[2],P_TIME(p),p->part_id);
}
else
{
printf("time is not reached");
}
fclose(fid1);
}

I can`t get all particle data after 1st time step.
I need all particles position data at the end of each time step. Do you have any method to do it?

Thanks and regards,
zyFan