Active nematics in corrugated channels

TL;DR

This study investigates how corrugated channel boundaries influence the flow behavior of active nematic fluids, revealing boundary-induced flows and transition dynamics through multiparticle collision simulations.

Contribution

It demonstrates the significant impact of boundary corrugations on flow transitions and states in active nematic fluids, using adapted multiparticle collision dynamics simulations.

Findings

Corrugations induce boundary-driven active flows.

Flow transition depends on wall curvature and channel width.

Corrugated channels alter the onset and nature of spontaneous flows.

Abstract

Active nematic fluids exhibit complex dynamics in both bulk and in simple confining geometries. However, complex confining geometries could have substantial impact on active spontaneous flows. Using multiparticle collision dynamics simulations adapted for active nematic particles, we study the dynamic behaviour of an active nematic fluid confined in a corrugated channel. The transition from a quiescent state to a spontaneous flow state occurs from a weak swirling flow to a strong coherent flow due to the presence of curved-wall induced active flows. We show that active nematic fluid flows in corrugated channels can be understood in two different ways: (i) as the result of an early or delayed flow transition when compared with that in a flat-walled channel of appropriate width and (ii) boundary-induced active flows in the corrugations providing an effective slip velocity to the coherent flows in the bulk. Thus, our work illustrates the crucial role of corrugations of the confining boundary in dictating the flow transition and flow states of active fluids.