Taylor dispersion in a soft channel

TL;DR

This paper develops a theory for solutal dispersion in soft microchannels, showing that channel softness enhances advection and dispersion, with implications for biology and microfluidics.

Contribution

It introduces a modified macro-transport equation accounting for channel compliance, revealing how softness influences solutal transport in steady and pulsatile flows.

Findings

Softness increases effective advection velocity.

Softness enhances dispersion coefficient.

Theory applies to steady and pulsatile flow configurations.

Abstract

Diffusion of a solute along a channel is enhanced by hydrodynamic flow, a phenomenon known as Taylor dispersion. In microfluidic applications, the compliance of the channel boundaries modifies the hydrodynamic flow and thus solutal transport. Here, we develop the theory of solutal dispersion in a soft, axisymmetric channel where the channel walls respond to the hydrodynamic pressure through a Winkler response. By deriving the modified macro-transport equation for the solutal concentration dynamics based on multiple-time-scale analysis, we explore the influence of softness on solutal transport for steady and pulsatile configurations. Our main finding is that softness enhances the effective advection velocity and dispersion coefficient, which might have practical implication in biology and microfluidic technology.