428243 Propulsion of a Pair of Spheres: Onset of Swimming Motion

Tuesday, November 10, 2015: 1:15 PM
Canyon B (Hilton Salt Lake City Center)
Daphne Klotsa1, Kyle A. Baldwin2, Richard J. A. Hill2, Roger M. Bowley2 and Michael R. Swift2, (1)Applied Physical Sciences, University of North Carolina at Chapel Hill, Durham, NC, (2)Physics, University of Nottingham, Nottingham, United Kingdom

We describe experiments and simulations demonstrating the propulsion of a neutrally-buoyant swimmer that consists of a pair of spheres attached by a spring, placed in a vibrating fluid. The vibration of the fluid induces relative motion of the spheres which, for sufficiently large amplitudes, can lead to motion of the center of mass of the two spheres. We find that the swimming speed obtained from both experiment and simulation agree and collapse onto a single curve if plotted as a function of the streaming Reynolds number, suggesting that the propulsion is related to streaming flows. There appears to be a critical onset value of the streaming Reynolds number for swimming to occur. The mechanism for swimming is traced to a jet of fluid generated by the relative motion of the spheres.

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See more of this Session: Active Colloidal Systems II
See more of this Group/Topical: Engineering Sciences and Fundamentals