Partial jamming and non-locality in dense granular flows

Particles and Grains Laboratory, School of Civil Engineering, The University of Sydney, 2006 NSW, Australia

^* e-mail: prashidha.kharel@sydney.edu.au
^** e-mail: pierre.rognon@sydney.edu.au

Published online: 30 June 2017

Abstract

Dense granular flows can exhibit non-local flow behaviours that cannot be predicted by local constitutive laws alone. Such behaviour is accompanied by the existence of diverging cooperativity length. Here we show that this length can be attributed to the development of transient clusters of jammed particles within the flow. By performing DEM simulation of dense granular flows, we directly measure the size of such clusters which scales with the inertial number with a power law. We then derive a general non-local relation based on kinematic compatibility for the existence of clusters in an arbitrary non-homogenous flow. The kinematic nature of this derivation suggests that non-locality should be expected in any material regardless of their local constitutive law, as long as transient clusters exist within the flow.