Microscopic mechanism for the shear-thickening of non-Brownian suspensions

TL;DR

This paper presents a model supported by simulations and experiments that explains the transition from continuous to discontinuous shear-thickening in dense suspensions, linking it to lubrication regimes and frictional properties at the particle contacts.

Contribution

It introduces a local Sommerfeld number to predict shear-thickening transition and demonstrates how volume fraction and boundary friction influence the nature of this transition.

Findings

Identification of a local Sommerfeld number governing shear-thickening transition

Demonstration that volume fraction affects the transition type

Experimental validation of the frictional control on shear-thickening

Abstract

We propose a simple model, supported by contact-dynamics simulations as well as rheology and friction measurements, that links the transition from continuous to discontinuous shear-thickening in dense granular pastes to distinct lubrication regimes in the particle contacts. We identify a local Sommerfeld number that determines the transition from Newtonian to shear-thickening flows, and then show that the suspension's volume fraction and the boundary lubrication friction coefficient control the nature of the shear-thickening transition, both in simulations and experiments.