title: Unified theory of inertial granular flows and non-Brownian suspensions.
abstract: Rheological properties of dense flows of hard particles are singular as one approaches the jamming threshold where flow ceases both for aerial granular flows dominated by inertia and for over-damped suspensions. Concomitantly, the length scale characterizing velocity correlations appears to diverge at jamming. Here we introduce a theoretical framework that proposes a tentative, but potentially complete, scaling description of stationary flows. Our analysis, which focuses on frictionless particles, applies both to suspensions and inertial flows of hard particles. We compare our predictions with the empirical literature, as well as with novel numerical data. Overall, we find a very good agreement between theory and observations, except for frictional inertial flows whose scaling properties clearly differ from frictionless systems. For overdamped flows, more observations are needed to decide if friction is a relevant perturbation. Our analysis makes several new predictions on microscopic dynamical quantities that should be accessible experimentally.
authors.affiliation: New York University, Center for Soft Matter Research, 4 Washington Place, New York, New York 10003, USA.
authors.forename: E
authors.initials: E
authors.lastname: DeGiuli
authors.affiliation: Facultad de Física, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile.
authors.forename: G
authors.initials: G
authors.lastname: Düring
authors.affiliation: New York University, Center for Soft Matter Research, 4 Washington Place, New York, New York 10003, USA.|Institute for Theoretical Physics, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Lerner
authors.affiliation: New York University, Center for Soft Matter Research, 4 Washington Place, New York, New York 10003, USA.
authors.forename: M
authors.initials: M
authors.lastname: Wyart