Hello everyone.
I'm trying to study the interaction between a randomly packed bed and a gas flowing through it. I would like the packed bed to be a representative volume element of a larger system, so the bulk of that system. To do so I should use periodic boundaries along all the directions. The problem is that the particles cannot be confined within walls (otherwise the geometrical periodicity is lost) and in such a configuration they are transported by the fluid flow (literally a stream of particles is formed). Furthermore, if the particles are subject to the gravity field, they also start falling along the direction of the gravity force.
So my question is: is there any way to have a packed bed interacting with a fluid flow and representing the bulk of a larger system with the particles that don't give rise to a stream of particles following the force fields they are subject to but that remain confined in an infinite array of particles?
I hope some of you can help me.
Thank you in advance,
Cheers.