hi

I want to write a UDF about particle track. who can tell me how to get the the particle current position in UDF. thanks

You can use Postprocessing for the Discrete Phase. You can use step- by-step reports of the particle position, velocity. or write reust to file.

thank you

I want to calculate the multiphase flow .And I want to give a centripetal acceleration to particle.I must get the current position of particle in my UDF program not in postprocessing.

In UDF Use's Guide 5.4.1 "Melting Index Along a Particle Trajectory" ,there is a example program.

the followed is the program I modify for my project

#include "udf.h"

#include "dpm.h"

#define C_acceler 30.0 /* centripetal acceleration */

DEFINE_DPM_BODY_FORCE(particle_body_force, p, i) {

real y,z; real alpha; face_t f;

float bforce; /* centripetal force */

y = p->state.pos[1]; /* particle y axis coordinate */ z = p->state.pos[2]; /* particle z axis coordinate*/

alpha = acos(fabs(z)/(sqrt(pow(z,2)+pow(y,2))));

if(z>0)

{

if(y>0)

{

if(i==1) bforce=-C_acceler*sin(alpha)*P_MASS(p)*9.8;

else if(i==2) bforce=-C_acceler*cos(alpha)*P_MASS(p)*9.8;

}

else

{

if(i==1) bforce=C_acceler*sin(alpha)*P_MASS(p)*9.8;

else if(i==2) bforce=-C_acceler*cos(alpha)*P_MASS(p)*9.8;

}

}

else

{

if(y>0)

{

if(i==1) bforce=-C_acceler*sin(alpha)*P_MASS(p)*9.8;

else if(i==2) bforce=C_acceler*cos(alpha)*P_MASS(p)*9.8;

}

else

{

if(i==1) bforce=C_acceler*sin(alpha)*P_MASS(p)*9.8;

else if(i==2) bforce=C_acceler*cos(alpha)*P_MASS(p)*9.8;

}

}

return (bforce);

}

but the program can not pass the compile. FLUENT show error in the line "y = p->state.pos[1]; /* particle y axis coordinate */ z = p->state.pos[2]; /* particle z axis coordinate*/" with message " structure inference reference not implement " Could you help me find what is wrong with it. or is there another way to give a force that change with time and position to the particle . thank you very much

Hi: I don't know why you want to add centripetal acceleration to particle. In my case. I simulate particle flow in 180degree bend tube. Particle flow in bend tube, it will get centripetal force, and hit tube. Particle ¡¥s Trajectory was decided from fluid flow. Can you tell me why you want to add centripetal acceleration to particle? Thanks!!

hi thank you

the flow field in a column container with a exit. and the container in a curve motion. so the particle in the flow field have a body force change with position and time. if you konw how to resolve it ,please tell me thanks