Abstract

At the micron scale, inertia is completely negligible in an aqueous environment. This means that microorganisms swimming in water had to invent their own strategies to move forward.

I will explain these strategies at a few examples and demonstrate that the physics at low Reynolds number allows for interesting non-linear dynamics such as synchronization and Hopf bifurcation.

In particular, I will talk about a biomimetic flagellum or cilium. This is a long elastic filament that has been used to construct an artificial swimmer or to transport fluid. I will then demonstrate how an array of cilia synchronize into metachronal waves and finally introduce how we model bacterial locomotion. Bacteria move forward with the help of a rotating bundel of helical filaments. Modeling these filaments and their actuation by a rotary motor offers interesting new insights into the problem.