Channel flows of deformable nematics

TL;DR

This paper investigates how deformability of nematic particles influences channel flows, revealing complex behaviors like shape oscillations, flow alignment, and banding, with implications for microfluidic applications.

Contribution

It introduces a continuum model capturing the effects of deformability on nematic flow dynamics, including nonlinear coupling and flow-induced pattern formation.

Findings

Deformability causes nonlinear coupling of strain rate and vorticity.

Shape oscillations and flow alignment occur in simple shear flows.

Particle deformability induces banding and complex behaviors in Poiseuille flow.

Abstract

We describe channel flows in a continuum model of deformable nematic particles. In a simple shear flow, deformability leads to a nonlinear coupling of strain rate and vorticity, and results in shape oscillations or flow alignment. The final steady state can depend on initial conditions, and we explain this behaviour by considering a phase space representation of the dynamics. In Poiseuille flow, particle deformability and nematic elasticity induce banding, where particles near the walls are aligned, and those near the centre of the channel oscillate in direction and shape. Our results show that particle deformability can lead to complex behaviour even in simple flows, suggesting new microfluidic experiments.