On the Fluid Dynamical Effects of Synchronization in Side-by-Side Swimmers

Ramiro Godoy-Diana (1) , Jérôme Vacher (1) , Verónica Raspa (1) , Benjamin Thiria (1)

1 PMMH - Physique et mécanique des milieux hétérogenes (UMR 7636)

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.

Mots clés: collective swimming; bio-inspired swimmers; fluid-structure interaction; self-propulsion; synchronization; fish schooling

Domaines: Mécanique des fluides [physics.class-ph]

Ramiro Godoy-Diana, Jérôme Vacher, Verónica Raspa, Benjamin Thiria. On the Fluid Dynamical Effects of Synchronization in Side-by-Side Swimmers. Biomimetics, 2019, 4 (4), pp.77. ⟨10.3390/biomimetics4040077⟩. ⟨hal-02400116⟩