Biophysical Fluid Dynamics in a Petri Dish

Fuente: arXiv
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Auteurs principaux: Fortune, George T., Lauga, Eric, Goldstein, Raymond E.
Format: Preprint
Publié: 2024
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author Fortune, George T.
Lauga, Eric
Goldstein, Raymond E.
author_facet Fortune, George T.
Lauga, Eric
Goldstein, Raymond E.
contents The humble Petri dish is perhaps the simplest setting in which to examine the locomotion of swimming organisms, particularly those whose body size is tens of microns to millimetres. The fluid layer in such a container has a bottom no-slip surface and a stress-free upper boundary. It is of fundamental interest to understand the flow fields produced by the elementary and composite singularities of Stokes flow in this geometry. Building on the few particular cases that have previously been considered in the literature, we study here the image systems for the primary singularities of Stokes flow subject to such boundary conditions - the stokeslet, rotlet, source, rotlet dipole, source dipole and stresslet - paying particular attention to the far-field behavior. In several key situations, the depth-averaged fluid flow is accurately captured by the solution of an associated Brinkman equation whose screening length is proportional to the depth of the fluid layer. The case of hydrodynamic bound states formed by spinning microswimmers near a no-slip surface, discovered first using the alga $Volvox$, is reconsidered in the geometry of a Petri dish, where the power-law attractive interaction between microswimmers acquires unusual exponentially screened oscillations.
format Preprint
id arxiv_https___arxiv_org_abs_2402_08374
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Biophysical Fluid Dynamics in a Petri Dish
Fortune, George T.
Lauga, Eric
Goldstein, Raymond E.
Soft Condensed Matter
Fluid Dynamics
Cell Behavior
The humble Petri dish is perhaps the simplest setting in which to examine the locomotion of swimming organisms, particularly those whose body size is tens of microns to millimetres. The fluid layer in such a container has a bottom no-slip surface and a stress-free upper boundary. It is of fundamental interest to understand the flow fields produced by the elementary and composite singularities of Stokes flow in this geometry. Building on the few particular cases that have previously been considered in the literature, we study here the image systems for the primary singularities of Stokes flow subject to such boundary conditions - the stokeslet, rotlet, source, rotlet dipole, source dipole and stresslet - paying particular attention to the far-field behavior. In several key situations, the depth-averaged fluid flow is accurately captured by the solution of an associated Brinkman equation whose screening length is proportional to the depth of the fluid layer. The case of hydrodynamic bound states formed by spinning microswimmers near a no-slip surface, discovered first using the alga $Volvox$, is reconsidered in the geometry of a Petri dish, where the power-law attractive interaction between microswimmers acquires unusual exponentially screened oscillations.
title Biophysical Fluid Dynamics in a Petri Dish
topic Soft Condensed Matter
Fluid Dynamics
Cell Behavior
url https://arxiv.org/abs/2402.08374