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On the Fluid Dynamical Effects of Synchronization in Side-by-Side Swimmers
Ramiro Godoy-Diana1, Jérôme Vacher1, Veronica Raspa1
1Laboratoire de Physique et Mécanique des Milieux Hétérogènes (PMMH, UMR 7636), CNRS, ESPCI Paris-PSL University, Sorbonne Université, Université de Paris, F-75005 Paris, France.
Abstract:
In-phase and anti-phase synchronization of neighboring swimmers is examined experimentally using two self-propelled independent flexible foils swimming side-by-side in a water tank. The foils are actuated by pitching oscillations at one extremity-the head of the swimmers-and the flow engendered by their undulations is analyzed using two-dimensional particle image velocimetry in their frontal symmetry plane. Following recent observations on the behavior of real fish, we focus on the comparison between in-phase and anti-phase actuation by fixing all other geometric and kinematic parameters. We show that swimming with a neighbor is beneficial for both synchronizations tested, as compared to swimming alone, with an advantage for the anti-phase synchronization. We show that the advantage of anti-phase synchronization in terms of swimming performance for the two-foil "school" results from the emergence of a periodic coherent jet between the two swimmers.
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