Fish can use coordinated fin motions to recapture their own vortex wake energy

Autor: Nils B. Tack, Kevin T. Du Clos, Brad J. Gemmell
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Royal Society Open Science, Vol 11, Iss 1 (2024)
Druh dokumentu: article
ISSN: 2054-5703
DOI: 10.1098/rsos.231265
Popis: During swimming, many fishes use pectoral fins for propulsion and, in the process, move substantial amounts of water rearward. However, the effect that this upstream wake has on the caudal fin remains largely unexplored. By coordinating motions of the caudal fin with the pectoral fins, fishes have the potential to create constructive flow interactions which may act to partially recapture the upstream energy lost in the pectoral fin wake. Using experimentally derived velocity and pressure fields for the silver mojarra (Eucinostomus argenteus), we show that pectoral–caudal fin (PCF) coordination enables the circulation and interception of pectoral fin wake vortices by the caudal fin. This acts to transfer energy to the caudal fin and enhance its hydrodynamic efficiency at swimming speeds where this behaviour occurs. We also find that mojarras commonly use PCF coordination in nature. The results offer new insights into the evolutionary drivers and behavioural plasticity of fish swimming as well as for developing more capable bioinspired underwater vehicles.
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