Microswimming under a wedge-shaped confinement

Abstract

Artificial and living microswimmers encounter a large variety of geometric confinements and surfaces in the biological world. Here, we study the low-Reynolds-number dynamics of a microswimmer enclosed by a wedge-shaped free-slip interface. For various opening angles of the wedge, we derive an exact solution for the resulting flow fields using the method of images. In this way, the hydrodynamic interactions between the swimmer and the confining interfaces are examined. In particular, we find attraction or repulsion by the wedge depending on the propulsion mechanism (pusher- or puller-type) and the opening angle of the wedge. Our description should be related to the dynamics of microswimmers in free-standing liquid films of spatially varying thickness.