SeminarPast EventFluid Dynamics

Hydrodynamic shape of microorganisms: Generalised Jeffery orbits

Schedule
Wednesday, March 17, 2021
09:00 UTC
Kenta Ishimoto

Dr

Kyoto University

Host: BioActive Fluids

Event Information

Host

BioActive Fluids

Duration

70 minutes

Abstract

'Shape' of microorganisms are diverse. However, we sometimes approximate them as a sphere or a spheroid when we mathematically model the hydrodynamics of motile and non-motile cells. Such a geometrical simplification can be theoretically validated for motions in a linear background flow, since the dynamics, known as the Jeffery orbit, only contain a single geometric parameter, called the Bretherton constant. In this talk, we generalise the Jeffery equations for a chiral axisymmetric object using the low-Reynolds-number hydrokinetic symmetry and then demonstrate that the dynamics of a certain type of chiral object in a fluid flow are characterised by a new chiral parameter in addition to the Bretherton constant. We also discuss how the generalised Jeffery orbits are applied to biased locomotion of bacteria in a bulk shear flow and we will share the idea of hydrodynamic `shape' of microorganisms to simplify the description of their dynamics.

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