Segregation forces in dense granular flows: Closing the gap from single intruders to mixtures

TL;DR

This paper develops a comprehensive model for segregation forces in dense granular flows, extending understanding from isolated intruders to complex mixtures with cooperative effects, using simulations and a novel virtual-spring approach.

Contribution

It introduces a new model for segregation forces that applies to finite-concentration mixtures, bridging the gap from single intruder to dense granular mixtures.

Findings

Model accurately predicts segregation forces across various conditions.

Identifies concentration thresholds for single intruder assumptions.

Provides insights into pressure partitioning in granular mixtures.

Abstract

Using simulations and a virtual-spring-based approach, we measure the segregation force, Fseg, over a range of size-bidisperse mixture concentrations, particle size ratios, and shear rates to develop a model for Fseg that extends its applicability from the well-studied non-interacting intruders regime to finite-concentration mixtures where cooperative phenomena occur. The model predicts the concentration below which the single intruder assumption applies and provides an accurate description of the pressure partitioning between species.