Conferences - Seminars

09SEP
2015
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  Wednesday 9 September 2015 13:30 - 14:30 ME B10

The role of elasticity for swimming micro-organisms

By Eric Lauga, University of Cambridge
Bio: since 2013: Fellow and College Lecturer in Mathematics - Trinity College, Cambridge
since 2013: University Senior Lecturer - University of Cambridge
2010-2013: Associate Professor - University of California, San Diego (USA)
2007-2010: Assistant Professor - University of California, San Diego (USA)
2006-2007: Assistant Professor - Massachusetts Institute of Technology (USA)
2005-2006: Postdoctoral Associate - Massachusetts Institute of Technology (USA)
2005: Lecturer - Harvard University (USA)

Many microbes (for ex. bacteria or green algae) possess flagella, slender whiplike appendages which are actuated in a periodic fashion in fluids and allow the cells to self-propel. We consider two problems in which elasticity of the flagella play a crucial role in the physics of locomotion. First, motivated by recent experiments, we consider the problem of microbial locomotion in complex, non-Newtonian fluids. While past theoretical work seems to indicate that viscoelasticity should systematically hinder locomotion, experimental observations suggest that locomotion enhancement is possible. In this talk, we present an overview of experimental results on the topic and propose a physical mechanism leading to enhanced swimming, which we quantify mathematically. Second, we consider the problem of bacterial bundling of bacterial swimming. Bacteria possess multiple flagella which interact hydrodynamically, synchronize, and can form a tight bundle behind a swimming cell. Most past theoretical work has approached the problem of bundling using numerical computations. Here, we present an asymptotic treatment of the interactions between elastic rotating filaments. We first show how to asymptotically compute the hydrodynamic kernels governing hydrodynamic interactions in the case of long filaments, and we then use these results to derive the nonlocal, nonlinear, equations of motions of each filament.

Organization Laboratory of Fluid Mechanics and Instabilities (LFMI)

Contact Prof. François Gallaire

Accessibility General public

Admittance Free