An introduction to the hydrodynamics of swimming microorganisms

This manuscript is a summary of a set of lectures given at the Geilo School 2013 Soft Matter Confinement: from Biology to Physics. It aims to provide an introduction to the hydrodynamics that underlies the way in which microorganisms, such as bacteria and algae, and fabricated microswimmers, swim. We focus on two features peculiar to bacterial swimming: the Scallop theorem and the dipolar nature of the far flow field. We discuss the consequences of these to the velocity field of a swimmer suspension and to the motion of passive tracers as a bacterium swims past.