On the Fluid Dynamical Effects of Synchronization in Side-by-Side Swimmers.

Ramiro Godoy-Diana,Jérôme Vacher,Veronica Raspa,Benjamin Thiria

doi:10.3390/biomimetics4040077

Abstract

In-phase and anti-phase synchronization of neighboring swimmers is examined experimentally using two self-propelled independent flexible foils swimming side-by-side in a water tank. The foils are actuated by pitching oscillations at one extremity—the head of the swimmers—and the flow engendered by their undulations is analyzed using two-dimensional particle image velocimetry in their frontal symmetry plane. Following recent observations on the behavior of real fish, we focus on the comparison between in-phase and anti-phase actuation by fixing all other geometric and kinematic parameters. We show that swimming with a neighbor is beneficial for both synchronizations tested, as compared to swimming alone, with an advantage for the anti-phase synchronization. We show that the advantage of anti-phase synchronization in terms of swimming performance for the two-foil “school” results from the emergence of a periodic coherent jet between the two swimmers.

Highlights

The interaction between neighboring individuals constitutes the fundamental fabric of collective dynamics [1]
The interactions between multiple swimmers may significantly impact the performance or cost of locomotion associated with fish schooling, as each swimmer moves in a non-uniform and unsteady flow created by its neighbors
The goal of the present work is to examine the hydrodynamics of a basic experiment of the interaction between two neighboring swimmers, which we model as undulating flexible foils

Summary

Introduction

The interaction between neighboring individuals constitutes the fundamental fabric of collective dynamics [1]. On the other hand, zooming into the problem of a single swimmer, despite the successes of Lighthill’s theory to describe the mechanics of fish swimming [9], the ubiquitous problems of the interaction between a swimmer and its environment are out of its reach. This environment can be a wall, a substrate (a significant number of works have explored this problem in different contexts [10,11,12,13]), or another neighboring swimmer.

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Conclusion