# Hydrodynamic interaction between two elastic microswimmers

## TL;DR

This study models the hydrodynamic interactions between two elastic microswimmers composed of spheres and springs, revealing how their velocities and states depend on their relative phase and distance.

## Contribution

It introduces a detailed model of elastic microswimmers with cyclic spring length changes and analyzes their interactions and velocity behaviors.

## Key findings

- Mean velocity of two swimmers is less than that of a single swimmer.
- Swimmers can be in bound or unbound states depending on phase difference.
- Interaction effects depend on symmetry and distance between swimmers.

## Abstract

We investigate the hydrodynamic interaction between two elastic swimmers which are composed of three spheres and two harmonic springs. In this model, the natural length of each spring is assumed to undergo a prescribed cyclic change, representing internal states of the swimmer [K. Yasuda et al., J. Phys. Soc. Jpn. 86, 093801 (2017)]. We obtain the average velocities of two identical elastic swimmers as a function of the distance between them both for structurally asymmetric and symmetric swimmers. We show that the mean velocity of the two swimmers is always smaller than that of a single elastic swimmer. The swimming state of two swimmers can be either bound or unbound depending on the relative phase difference between the two elastic swimmers.