We analyzed the effect of confinement on the effective diffusion of a run-and-tumble E. coli-like flagellated microswimmer. We used a simulation protocol where the run phases are obtained via a fully resolved swimming problem, i.e., Stokes equations for the fluid coupled with rigid-body dynamics for the microorganism, while tumbles and collisions with the walls are modeled as random reorientation of the microswimmer. For weak confinement, the swimmer is trapped in circular orbits close to the solid walls. In this case, optimal diffusivity is observed when the tumbling frequency is comparable with the angular velocity of the stable orbits. For strong confinement, stable circular orbits disappear and the diffusion coefficient monotonically decreases with the tumbling rate. Our findings are generic and can be potentially applied to other natural or artificial chiral microswimmers that follow circular trajectories close to an interface or in confined geometries.

Diffusivity of E. coli -like microswimmers in confined geometries: the role of the tumbling rate / Guccione, Giorgia; Pimponi, Daniela; Gualtieri, Paolo; Chinappi, Mauro. - In: PHYSICAL REVIEW. E. - ISSN 2470-0045. - STAMPA. - 96:4(2017). [10.1103/PhysRevE.96.042603]

Diffusivity of E. coli -like microswimmers in confined geometries: the role of the tumbling rate

Pimponi, Daniela;Gualtieri, Paolo;Chinappi, Mauro
2017

Abstract

We analyzed the effect of confinement on the effective diffusion of a run-and-tumble E. coli-like flagellated microswimmer. We used a simulation protocol where the run phases are obtained via a fully resolved swimming problem, i.e., Stokes equations for the fluid coupled with rigid-body dynamics for the microorganism, while tumbles and collisions with the walls are modeled as random reorientation of the microswimmer. For weak confinement, the swimmer is trapped in circular orbits close to the solid walls. In this case, optimal diffusivity is observed when the tumbling frequency is comparable with the angular velocity of the stable orbits. For strong confinement, stable circular orbits disappear and the diffusion coefficient monotonically decreases with the tumbling rate. Our findings are generic and can be potentially applied to other natural or artificial chiral microswimmers that follow circular trajectories close to an interface or in confined geometries.
2017
low-reynolds-number; hydrodynamics; bacteria; motion; competition; chemotaxis; swimmers; films
01 Pubblicazione su rivista::01a Articolo in rivista
Diffusivity of E. coli -like microswimmers in confined geometries: the role of the tumbling rate / Guccione, Giorgia; Pimponi, Daniela; Gualtieri, Paolo; Chinappi, Mauro. - In: PHYSICAL REVIEW. E. - ISSN 2470-0045. - STAMPA. - 96:4(2017). [10.1103/PhysRevE.96.042603]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1096577
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