Random motion of a circle microswimmer in a random environment

TL;DR

This study investigates how a circle microswimmer's movement is affected by random obstacles and noise, revealing conditions that either enhance or suppress its transport capabilities.

Contribution

It introduces a simulation framework analyzing the combined effects of quenched disorder and stochastic noise on microswimmer transport in disordered environments.

Findings

Increasing noise or disorder initially amplifies diffusion.

At high randomness, transport is strongly suppressed.

Transport behavior is explained by comparing motion and collision time scales.

Abstract

We simulate the dynamics of a single circle microswimmer exploring a disordered array of fixed obstacles. The interplay of two different types of randomness, quenched disorder and stochastic noise, is investigated to unravel their impact on the transport properties. We compute lines of isodiffusivity as a function of the rotational diffusion coefficient and the obstacle density. We find that increasing noise or disorder tends to amplify diffusion, yet for large randomness the competition leads to a strong suppression of transport. We rationalize both the suppression and amplification of transport by comparing the relevant time scales of the free motion to the mean period between collisions with obstacles.