title: Enhanced diffusion by reciprocal swimming.
abstract: Purcell's scallop theorem states that swimmers deforming their shapes in a time-reversible manner ("reciprocal" motion) cannot swim. Using numerical simulations and theoretical calculations we show here that, in a fluctuating environment, reciprocal swimmers undergo, on time scales larger than that of their rotational diffusion, diffusive dynamics with enhanced diffusivities, possibly by orders of magnitude, above normal translational diffusion. Reciprocal actuation does therefore lead to a significant advantage over nonmotile behavior for small organisms such as marine bacteria.
authors.affiliation: Department of Mechanical and Aerospace Engineering, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0411, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Lauga
mesh_terms: D001419:Bacteria / Q000378:metabolism; D001696:Biomechanical Phenomena; D004058:Diffusion; D006801:Humans; D008954:Models, Biological; D009068:Movement; D012399:Rotation; D013550:Swimming; D014871:Water Microbiology