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Role of Correlations in the Collective Behavior of Microswimmer Suspensions

Research output: Contribution to journalArticle

Original languageEnglish
Article number028005
Number of pages6
JournalPhysical Review Letters
Volume119
Issue number2
DOIs
StatePublished - 13 Jul 2017

Abstract

In this Letter, we study the collective behavior of a large number of self-propelled microswimmers immersed in a fluid. Using unprecedentedly large-scale lattice Boltzmann simulations, we reproduce the transition to bacterial turbulence. We showthat, even well belowthe transition, swimmersmove in a correlated fashion that cannot be described by a mean-field approach. We develop a novel kinetic theory that captures these correlations and is nonperturbative in the swimmer density. To provide an experimentally accessible measure of correlations, we calculate the diffusivity of passive tracers and reveal its nontrivial density dependence. The theory is in quantitative agreement with the lattice Boltzmann simulations and captures the asymmetry between pusher and puller swimmers below the transition to turbulence.

Research areas

  • ACTIVE MATTER, MICRO-SWIMMERS, MOTION, TURBULENCE, DIFFUSION, EMERGENCE, DYNAMICS, SYSTEMS

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