title: Hydrodynamic interaction between two swimmers at low Reynolds number.
abstract: We investigate the hydrodynamic interactions between micro-organisms swimming at low Reynolds number. By considering simple model swimmers, and combining analytic and numerical approaches, we investigate the time-averaged flow field around a swimmer. At short distances the swimmer behaves like a pump. At large distances the velocity field depends on whether the swimming stroke is invariant under a combined time-reversal and parity transformation. We then consider two swimmers and find that the interaction between them consists of two parts: a passive term, independent of the motion of the second swimmer, and an active term resulting from the simultaneous swimming action of both swimmers. The swimmer-swimmer interaction is a complicated function of their relative displacement, orientation, and phase, leading to motion that can be attractive, repulsive, or oscillatory.
authors.affiliation: Rudolf Peierls Centre for Theoretical Physics, 1 Keble Road, Oxford OX1 3NP, United Kingdom.
authors.forename: C M
authors.initials: CM
authors.lastname: Pooley
authors.forename: G P
authors.initials: GP
authors.lastname: Alexander
authors.forename: J M
authors.initials: JM
authors.lastname: Yeomans
mesh_terms: D000818:Animals; D008954:Models, Biological; D009068:Movement / Q000502:physiology*; D010247:Paramecium / Q000502:physiology