thanks for the stopped the mass injection of the particle after certain flow time . I was expecting that the particle which are still in the domain will be pushed further down by the continuous incoming fluid. nBut after running the simulation for almost a day, they stick to the wall of section 2 and not moving to section 3 even after changing section-2 wall conditions to reflect. Is it the higher particle density issue or what do you think ? ni am guessing that particle is too heavy than fluid . So they settled down to wall of sec-2. nwhat is your idea about ? nthanks in advancen