A microscopic picture of erosion and sedimentation processes in dense granular flows

TL;DR

This paper develops a microscopic model for dense granular flows that captures erosion and sedimentation processes, providing detailed phase diagrams consistent with experiments and simulations.

Contribution

It introduces a new microscopic model incorporating friction, geometry, and nonlocal effects to describe solid-fluid phase exchanges in granular flows.

Findings

Predicts phase diagram with erosion, sedimentation, and stationary regimes

Quantitative agreement with experiments and simulations

Provides detailed microscopic understanding of phase transitions

Abstract

Gravity-driven flows of granular matter are involved in a wide variety of situations, ranging from industrial processes to geophysical phenomena, such as avalanches or landslides. These flows are characterized by the coexistence of solid and fluid phases, whose stability is directly related to the erosion and sedimentation occurring at the solid-fluid interface. To describe these mechanisms, we build a microscopic model involving friction, geometry, and a nonlocal cooperativity emerging from the propagation of collisions. This new picture enables us to obtain a detailed description of the exchanges between the fluid and solid phases. The model predicts a phase diagram including erosion, sedimentation, and stationary-flow regimes, in quantitative agreement with experiments and discrete-element-method simulations.