Counting particles in transient simulation using Fluent DPM method
 

Hello,

I am using Fluent DPM method with one-way coupling in Fluent. I need to write a UDF that counts the number of particles in its surrounding as the particles flow in a fluid. I have about 200 particles, and with each particle location as the center of the spherical volume, the number of particles within the volume of a specified radius is required.
I am doing a transient simulation, in which all particles advance with time step, so it should be practical to count the number of particles. But cant find the right DPM macro for this purpose.
Any help will be highly appreciated.

Thank you.