Special boundary for multiphase flows
 

Hi. I'm working on a multiphase application where I would like to have a special boundary applied. I'm doing a cyclone calculation where the mass loading is quite dense, so instead of using a DPM approach I'm trying to use the mixture model. The boundary I would like to have modified is the bottom boundary of the cyclone where I want the gas to consider it as a wall, but for the solid phase I would like to have the same boundary as an outflow (with no reverse flow), so it works as a "trap" for the solid phase, but leaving the gas phase inside the domain. Anyone knows how to do this?