[Ari]

Hi everyone!
I set a particles injection and I'm using an UDF in order to track the particles and export some particles related quantities at the end of each time step.The UDF simply executes a loop on the particles. The UDF used to work on a previuos version of fluent (6.3 if i can remember). The problem appears when the particles are released and tracked for the first time. The UDF saves the particles related data but at the next time step the particles suddenly disappear from the domain and fluent gives me number tracked=0. The problem seems to come from the UDF line "bin_particles_in_cells(d,TRUE);" when I remove that line the simulation works with the particle injection and the particles are tracked but the UDF doesn't save the files with particles information that it is supposed to save. This is my general UDF with the x position as quantity to be saved just as example for you.

#include "udf.h"
#include "surf.h"
DEFINE_EXECUTE_AT_END(execute_at_end)
{
FILE *fp=NULL;
char str[40];
Domain *d=Get_Domain(1);
cell_t c;
int ID=9;
Tracked_Particle *p;
Thread *t;
real id;
real my_time_p;
double posx
Alloc_Storage_Vars(d,SV_DPM_PARTICLE_BIN,SV_NULL);
bin_particles_in_cells(d,TRUE);
Thread *t=Lookup_Thread(d,ID);
begin_c_loop(c,t)
{
begin_particle_cell_loop(p,c,t)
{
id=p->part_id;
my_time_p=P_TIME(p);
posx=P_POS(p)[0];

sprintf(str,"./PATH/path%.0f.txt",id);
fp=fopen(str,"a");
fprintf(fp,"%-5.5e \n",posx);
fclose(fp);
}
end_particle_cell_loop(p,c,t)
}
end_c_loop(c,c_thread)
Free_Storage_Vars(d,SV_DPM_PARTICLE_BIN,SV_NULL);
Message("\nParticle Writing Done\n");
#endif
}

Anyone has any idea about what's going on with my simulation or had a similar problem?

[Ari]

I finally solved my problem if anyone is interested I can share the solution!

[Saidul]

Could you please share your solution?

Thanks in advance.
S.I.

[Ari]

Basically I changed my code in order to loop over the particles of the injection and not over the cells. It works pretty well. I don't know what they changed from the previous versions because my old code used to work on Fluent 6.3.
#include "udf.h"
#include "dpm.h"
#include "surf.h"

DEFINE_EXECUTE_AT_END(execute_at_end)
{
FILE *fp=0;
char str[40];
Domain *d=Get_Domain(1);
Particle *p;
Injection *I;
Injection *dpm_injections = Get_dpm_injections();
real id;
real my_time_p;
double posx,posy,posz;

loop(I,dpm_injections)
{
loop(p,I->p)
{
cell_t c;
Thread *c_thread;
c=P_CELL(p);
c_thread=P_CELL_THREAD(p);
posx=P_POS(p)[0];
posy=P_POS(p)[1];
posz=P_POS(p)[2];

sprintf(str,"H:/PATH/path%.0f.txt",id);
fp=fopen(str,"a");
fprintf(fp,"%-5.5e %-5.5e %-5.5e f\n",posx,posy,posz);
fclose(fp);
}
}
Message("\nParticle Writing Done\n");
}

[Narita]

Hello Ari. I have exactly the same problem in Ansys Fluent 14+ and 16.
(My thread on this problem: http://www.cfd-online.com/Forums/flu...tml#post602635)

Thank you so much for posting the solution, yet I'm still very interested in how to deal with bin_particles_in_cells(domain,TRUE).

I'll try my best and then come back to share the solution!