Hydrodynamic interactions between bacterial flagellar filaments

Hydrodynamic interactions are essential in many biological flows, from the collective self-organisation of micro-swimmers to the coordination of cilia and flagella into well-defined swimming gaits. In this talk, we show how to use an asymptotic expansion to compute the extended resistance matrix of two hydrodynamically-coupled slender filaments, valid when the inter-filament distance is greater than the filament length [1]. Next, we demonstrate how this analytical theory can be applied to the case of helical filaments and, in conjunction with slender-body theory (SBT) simulations, lead to valuable insights on the hydrodynamic synchronization [2] and the propulsive capacity of multiple rotating bacterial flagella.