Surya Deb
Ansys Employee
Hello, nI would recommend you to diagnose and debug in a systematic way. nWhat is the D_RATIO that you have used? Can you check by setting it to 1?nAlso I would recommend you to print out the mass of the particle at relevant locations in the UDF just to make sure if it is getting splashed, absorbed or reflected in a proper way.nDid you test this with different particle sizes to see if you observe the same behavior?nAlso make sure that your particle type is Inert as I believe the reflection using DEFINE_DPM_BC will only reflect particles of type Inert and will abort any tracking for other particle types.nRegards,nSDn