Collective entrainment and confinement amplify transport by schooling micro-swimmers

TL;DR

This study demonstrates that schooling micro-swimmers can significantly enhance fluid transport and cargo capacity in complex environments through collective entrainment and confinement, with experimental and theoretical validation.

Contribution

It introduces a combined experimental and modeling approach to quantify how collective entrainment amplifies transport by micro-swimmers in confined flows.

Findings

Entrainment volume exceeds the swimmer volume by over an order of magnitude.

Schooling micro-swimmers can efficiently transport materials into confined spaces.

Good agreement between experiments and the Brinkman squirmer model.

Abstract

Micro-swimmers can serve as cargo carriers that move deep inside complex flow networks. When a school collectively entrains the surrounding fluid, their transport capacity can be enhanced. This effect is quantified with good agreement between experiments with self-propelled droplets and a confined Brinkman squirmer model. The volume of liquid entrained can be much larger than the droplet itself, amplifying the effective cargo capacity over an order of magnitude, even for dilute schools. Hence, biological and engineered swimmers can efficiently transport materials into confined environments.