Swimming at low Reynolds number slip boundaries and interacting filaments
type: CreativeWork
description: Biological microorganisms swim in different types of fluids using a range of diverse motions and are often found in complex geometries. Their study is a rich field full of outstanding problems. One aspect that has attracted a lot of attention is the role played by hydrodynamic interactions, including those between a cell and its fluid environment (fluid-cell), or between neighbouring cells (cell-cell). These interactions can affect dramatically the dynamics of these swimmers. This dissertation investigates the dynamics of filaments interacting hydrodynamically with a fluid through slip boundary conditions or with other filaments and is composed of two separate parts. The first part of the thesis focuses on a single filament characterised by a slip boundary condition, which is a property displayed by many non-Newtonian fluids. I propose a waving sheet and a waving cylinder model to demonstrate a possible enhancement of swimming by such slip effect. The results are in good agreement with previous experimental and numerical studies. In subsequent work, I extend the classical slender-body theory to replace the no-slip boundary condition by a finite slip length. The second part of the thesis addresses the nature of hydrodynamic interactions between filaments - a phenomenon that occurs widely in the biological world. By developing a new method for integrating hydrodynamic singularities between interacting filaments, I show how the force on the filament can be evaluated analytically. Using this result, I study the specific problem of bacterial flagellar bundling. This complex process is studied in two steps. Firstly, using a simpler geometry, I propose a model with elastic filaments to reveal the dynamics of bundling and unbundling. I then expand upon this to consider the full helical geometry of a bacterial flagellum, and develop a theoretical model for the pathway to synchronization. In each case, either by considering simple geometries or through the use of asymptotic m…
abstract: Biological microorganisms swim in different types of fluids using a range of diverse motions and are often found in complex geometries. Their study is a rich field full of outstanding problems. One aspect that has attracted a lot of attention is the role played by hydrodynamic interactions, including those between a cell and its fluid environment (fluid-cell), or between neighbouring cells (cell-cell). These interactions can affect dramatically the dynamics of these swimmers. This dissertation investigates the dynamics of filaments interacting hydrodynamically with a fluid through slip boundary conditions or with other filaments and is composed of two separate parts. The first part of the thesis focuses on a single filament characterised by a slip boundary condition, which is a property displayed by many non-Newtonian fluids. I propose a waving sheet and a waving cylinder model to demonstrate a possible enhancement of swimming by such slip effect. The results are in good agreement with previous experimental and numerical studies. In subsequent work, I extend the classical slender-body theory to replace the no-slip boundary condition by a finite slip length. The second part of the thesis addresses the nature of hydrodynamic interactions between filaments - a phenomenon that occurs widely in the biological world. By developing a new method for integrating hydrodynamic singularities between interacting filaments, I show how the force on the filament can be evaluated analytically. Using this result, I study the specific problem of bacterial flagellar bundling. This complex process is studied in two steps. Firstly, using a simpler geometry, I propose a model with elastic filaments to reveal the dynamics of bundling and unbundling. I then expand upon this to consider the full helical geometry of a bacterial flagellum, and develop a theoretical model for the pathway to synchronization. In each case, either by considering simple geometries or through the use of asymptotic m…
author: Man, Yi
language: en
keywords: Hydrodynamic interaction, Low-Reynolds number flows, Slip boundaries, Filaments, Microswimmers, Flagella, Cillia, Elastohydrodynamics
license: https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/9ac6bb97-7846-41a3-8b3f-c05343441b99/download
license: https://www.rioxx.net/licenses/all-rights-reserved/
date published: 2017-05-16
date modified: 2026-07-22T22:24:00Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.85320