Brownian dynamics of a microswimmer

TL;DR

This paper investigates the dynamic behavior of a three-sphere microswimmer in viscous fluid, revealing a transition from dissipation to active propulsion with increasing spinning frequency, and modeling high-frequency diffusion as active particle motion.

Contribution

It introduces a simple three-sphere microswimmer model and characterizes its transition from dissipative to active propulsion regimes, including a high-frequency diffusion model.

Findings

Transition from dissipation to pumping regime at higher frequencies

Negative effective friction coefficient observed

High-frequency diffusion modeled as active particle with constant velocity

Abstract

We report on dynamic properties of a simple model microswimmer composed of three spheres and propelling itself in a viscous fluid by spinning motion of the spheres under zero net torque constraint. At a fixed temperature and increasing the spinning frequency, the swimmer demonstrates a transition from dissipation-dominated to a pumping-dominated motion regime characterized by negative effective friction coefficient. In the limit of high frequencies, the diffusion of the swimmer can be described by a model of an active particle with constant velocity.