A Model for the Threshold of the Rolling Transition

Abstract

A dynamic transition has been identified recently by numerical simulations in the case of a granular flow along a rotating boundary (Rioual and Le Quiniou (2011)). We showed that this transition appears above a certain critical microscopic friction coefficient particle/boundary µ* from which the particles roll without any sliding. We propose here a model at the scale of the microstructure which aimes to be close to the physical process considered and predicts also a threshold for the apparition of this dynamic transition. We discuss the discrepancy on a quantitative level in terms of friction properties at the contact.