[GiorgioDTU]

Hello CFD community,
It is my first post hear however i have been following the forum for quite a while looking for answers. My question has been applied before by several users but it does not seem that i get a clear answer.
So, i have domain which contains two regions which are separated by an internal interface. From one region i am injecting particles using the Lagrangian multiphase. I need to count the number of particles that exist at each region at every time.
I have already tried the boundary sampling but with no luck. Maybe i am doing it wrong so if someone could give clear directions of how to proceed would be great.
Element count does not work since it count the number of cell in the region. As i have understood the most viable procedure is through the boundary sampling.
Please help
Best,
Georgios