Discontinuous Shear Thickening of Frictional Hard-Sphere Suspensions

TL;DR

This paper demonstrates through numerical simulation that contact friction is crucial for discontinuous shear thickening in dense suspensions, revealing a transition between frictionless and frictional shear jammed states at a critical shear stress.

Contribution

It introduces a numerical scheme incorporating hydrodynamic interactions and granular contacts, showing friction's essential role in DST and identifying a shear stress-driven transition.

Findings

DST requires contact friction in simulations.

Two states: frictionless low viscosity and frictional shear jammed.

A critical shear stress separates the two states.

Abstract

Discontinuous shear thickening (DST) observed in many dense athermal suspensions has proven difficult to understand and to reproduce by numerical simulation. By introducing a numerical scheme including both relevant hydrodynamic interactions and granularlike contacts, we show that contact friction is essential for having DST. Above a critical volume fraction, we observe the existence of two states: a low viscosity, contactless (hence, frictionless) state, and a high viscosity frictional shear jammed state. These two states are separated by a critical shear stress, associated with a critical shear rate where DST occurs. The shear jammed state is reminiscent of the jamming phase of granular matter. Continuous shear thickening is seen as a lower volume fraction vestige of the jamming transition.