Life around the scallop theorem

TL;DR

This paper reviews how various strategies can bypass Purcell's scallop theorem, enabling effective locomotion at small scales where viscous forces dominate.

Contribution

It systematically examines methods to escape the constraints of the scallop theorem for small-scale swimming.

Findings

Identifies mechanisms to break the scallop theorem constraints

Classifies different strategies for small-scale locomotion

Provides insights into effective swimmer designs at low Reynolds numbers

Abstract

Locomotion on small scales is dominated by the effects of viscous forces and, as a result, is subject to strong physical and mathematical constraints. Following Purcell's statement of the scallop theorem which delimitates the types of swimmer designs which are not effective on small scales, we review the different ways the constraints of the theorem can be escaped for locomotion purposes.