Swimming by switching

TL;DR

This paper explores innovative swimming strategies that leverage fluid property changes during periodic shape deformations to achieve net motion, overcoming the scallop theorem limitations.

Contribution

It introduces two models utilizing fluid type switching based on deformation velocity magnitude and sign, including a delay-switching rule for bidirectional movement.

Findings

Net motion is achievable through fluid property switching.

Delay-switching enables both forward and backward swimming.

Models demonstrate effective strategies to bypass scallop theorem constraints.

Abstract

In this paper we investigate different strategies to overcome the scallop theorem. We will show how to obtain a net motion exploiting the fluid's type change during a periodic deformation. We are interested in two different models: in the first one that change is linked to the magnitude of the opening and closing velocity. Instead, in the second one it is related to the sign of the above velocity. An interesting feature of the latter model is the introduction of a delay-switching rule through a thermostat. We remark that the latter is fundamental in order to get both forward and backward motion.