Flow of a particle along a rotating wall

We study numerically and theoretically the flow of a particle along a rotating wall considering a viscoelastic interaction law. A typical trajectory of the particle along the wall consists in a first phase of successive jumps followed by a second phase of permanent contacts along the wall. We show in particular that there exists a critical friction coefficient between the particle and the wall for which the particle can roll without any sliding in the second phase. This critical friction coefficient appears to depend only on the normal coefficient of restitution of the particle. We examine also the influence of the rebounds in the flow of the particle. We give a physical interpretation of these effects