Unifying Suspension and Granular flows near Jamming

TL;DR

This paper reviews a unified theoretical framework describing the critical rheological behavior and diverging correlation length near the jamming transition in dense granular and suspension flows, supported by numerical evidence.

Contribution

It introduces a scaling theory that unifies the description of frictionless granular and suspension flows near jamming, including phase diagram analysis with friction effects.

Findings

The theory accurately predicts rheological singularities near jamming.

Numerical results support the scaling description of velocity correlations.

Friction modifies the phase diagram, defining regimes of validity.

Abstract

Rheological properties of dense flows of hard particles are singular as one approaches the jamming threshold where flow ceases, both for granular flows dominated by inertia, and for over-damped suspensions. Concomitantly, the lengthscale characterizing velocity correlations appears to diverge at jamming. Here we review a theoretical framework that gives a scaling description of stationary flows of frictionless particles. Our analysis applies both to suspensions and inertial flows of hard particles. We report numerical results in support of the theory, and show the phase diagram that results when friction is added, delineating the regime of validity of the frictionless theory.