[lmtlmt12@yahoo.com]

I need to fix the particle position in the Z direction to its initial value. The following is the UDF I tried:

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

DEFINE_DPM_SCALAR_UPDATE(fix_particle_z, c, t, initialize, p)
{
if (initialize)
{
TP_USER_REAL(p, 0) = TP_POS(p)[2];
}
else
{
TP_POS(p)[2] = TP_USER_REAL(p, 0);
}
}

The UDF can be compiled without any problem and is called by Fluent, but it seems the particle Z position is not fixed at its initial value. Does anyone know what is wrong with the UDF? Thank you in advance!