Regularized representation of bacterial hydrodynamics

Abstract

Fluid flows induced by a flagellated bacterial swimmer are often modeled as a simple force dipole, valid in the far field. Such representations neglect the inherent rotation of these bacteria as they swim, driven by a spinning helical flagellum or fascicle. Here, we present a refined swimmer representation that makes use of regularized singularities, retaining simplicity while capturing details of the complex flow field near the swimmer that have previously been absent from basic models. We illustrate the significance of this representation via a study of bacterial predator-prey dynamics, highlighting the importance of detailed hydrodynamics in models of bacterial interactions and bacterial active matter.