Flow fields and trajectories of microswimmers under confinement

The hydrodynamics of microswimmers under confinement is significantly more complex than in bulk fluids and is strongly influenced by the flow fields of the confined microswimmers. Using a reduced simulation model, we investigate the flow field and swimming trajectory of a microswimmer in a confined liquid film. The hydrodynamic interactions between the model swimmer and the confining boundaries are accounted through far-field hydrodynamic approximations using flow singularities as well as the method of images. We first demonstrate that the flow field generated by the microswimmer in the film is determined by the strength of the confinement and the strength of flow singularities induced by the swimmer's motion. We systematically explore how the change in flow field under different conditions influences the swimmer's trajectory. Finally, we contrast the difference in dynamics for pusher-type and puller-type swimmers in a confined liquid film. This works provides a better understanding on the dynamics of microswimmers in confined environments.