Athermal analogue of sheared dense Brownian suspensions

TL;DR

This study demonstrates that an athermal model with a logarithmic potential can replicate the rheological behavior of dense Brownian suspensions, highlighting a pressure-controlled analogy between colloidal glass transition and granular jamming.

Contribution

The paper introduces an athermal analogue model that captures the rheology of dense Brownian suspensions without adjustable parameters.

Findings

Both systems exhibit similar Herschel-Bulkley rheology when scaled appropriately.

The rheological response is governed by a characteristic stress scale and reorganization time.

A pressure-controlled framework links colloidal glass transition and granular jamming.

Abstract

The rheology of dense Brownian suspensions of hard spheres is investigated numerically beyond the low shear rate Newtonian regime. We analyze an athermal analogue of these suspensions, with an effective logarithmic repulsive potential representing the vibrational entropic forces. We show that both systems present the same rheology without adjustable parameters. Moreover, all rheological responses display similar Herschel-Bulkley relations once the shear stress and the shear rate are respectively rescaled by a characteristic stress scale and by a microscopic reorganization time-scale, both related to the normal confining pressure. This pressure-controlled approach, originally developed for granular flows, reveals a striking physical analogy between the colloidal glass transition and granular jamming.