Dear Dr. Amine and Robert,

After sending an email to Ansys Community Help, I am able to upload the photos now. I apologize for the inconvenience. Please read the problem description again, considering the screenshots this time.

Using the "Body of influence" feature in meshing, I have created a denser mesh in the vicinity of the walls (screens) but by changing the mesh resolution either in that area close to the walls or far away from them, I get different numbers of trapped particles after particle tracking.