Hydrodynamic Irreversibility in Particle Suspensions with Non-Uniform Strain

TL;DR

This paper investigates how non-uniform strain in particle suspensions causes a transition to irreversibility, driven by long-range correlated particle motion, differing from uniform shear scenarios.

Contribution

It extends understanding of irreversibility in suspensions by analyzing non-uniform strain effects and identifying long-range correlations as a key factor.

Findings

Irreversibility onset occurs despite partial shear-induced migration.

Long-range correlated particle motion persists at the channel center.

System remains irreversible due to particle activity at low strain regions.

Abstract

A dynamical phase transition from reversible to irreversible behavior occurs when particle suspensions are subjected to uniform oscillatory shear, even in the Stokes flow limit. We consider a more general situation with non-uniform strain (e.g. oscillatory channel flow), which is observed to exhibit markedly different dynamics. Self-organization and shear-induced migration only partially explain the delayed, simultaneous onset of irreversibility across the channel. The onset of irreversibility is accompanied by long-range correlated particle motion. This motion leads to particle activity even at the channel center, where the strain is negligible, and prevents the system from evolving into a reversible state.