472308 Two Spheres and a Spring Make a Good Swimmer

Monday, November 14, 2016
Market Street (Parc 55 San Francisco)
Daphne Klotsa1, Kyle A. Baldwin2, Richard J. A. Hill2, Michael R. Swift2 and Roger M. Bowley2, (1)Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, (2)Physics, University of Nottingham, Nottingham, United Kingdom

Rigid spherical particles in oscillating fluid flows form interesting patterns as a result of fluid mediated interactions, at intermediate Reynolds numbers. Here, through both experiments and simulations, we show that two spheres under horizontal vibration align themselves at right angles to the oscillation and sit with a gap between them, which scales in a non-classical way with the boundary layer thickness. A large number of spherical particles form strings perpendicular to the direction of oscillation. Investigating the details of the interactions we find that the driving force is the nonlinear hydrodynamic effect of steady streaming. We then design a simple swimmer (two-spheres-and-a-spring) that utilizes steady streaming in order to propel itself and discuss the nature of the transition at the onset of swimming as the Reynolds number gradually increases. We discuss our latest results on the collective behavior of simple swimmers at intermediate Reynolds numbers. 

Extended Abstract: File Not Uploaded
See more of this Session: Poster Session: Fluid Mechanics (Area 1J)
See more of this Group/Topical: Engineering Sciences and Fundamentals