Young Researchers Workshop:
Multiscale phenomena: modeling, analysis and computation

How does the flagellum affect bacterial swimming?

Magali Tournus

INRIA Rocquencourt
[SLIDES]

Understanding the motion of micro-swimmers is essential to derive models at the macroscopic scale. Many bacteria use rotating elastic flagella for swimming motility. The flagellum can be easily deformed by an external shear flow leading to complex bacterial trajectories. We develop a model of a self-propelled flagellated swimmer, composed with a strongly coupled system of ODE's and a 4th order parabolic PDE. We examine the effects of flagella flexibility on the navigation of bacteria in two fundamental shear flows: a planar shear flow and a Poiseuille flow, realized in long channels. Numerical results and asymptotic analysis suggest that there is a variety of nontrivial effects stemming from the interplay of self-propulsion, elasticity, and shear-induced flagellar bending.