[simo11]

Hi, I want to set a particular boundary condition for the bottom of a channel so that particles can be reflected when they are near to the wall but they haven't touched it yet.
I'm new in writing UDF: I tried to use and modify the DEFINE_DPM_BC using a check on the z-coordinate of the particle (z=0 indicates the bottom of the channel, pointing outside it) to invert the z-velocity when necessary; when I try to compile this UDF, Fluent says that can't open the udf_library and it's impossible to find the specified file.

Please, can you help me?

This is the UDF text:

#include"udf.h"
DEFINE_DPM_BC (bc_reflect, p, t, f, f_normal, dim)

{
int i;
if ( P_POS (p) [2] >= -P_DIAM (p))
{

P_VEL (p) [2] = -P_VEL (p) [2];
for (i=0; i<3; i++)
P_VEL0 (p) [i] = P_VEL (p) [i];
}
return PATH_ACTIVE;
}

Thank you very much!