Fine-tuning near-boundary swimming equilibria using asymmetric kinematics.

Autor: Liu L; Mechanical & Aerospace Engineering, University of Virginia, Charlottesville, VA 22904, United States of America., Zhong Q; Mechanical Engineering, Iowa State University, Ames, IA 50011, United States of America., Han T; Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18015, United States of America., Moored KW; Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18015, United States of America., Quinn DB; Mechanical & Aerospace Engineering, Electrical & Computer Engineering, University of Virginia, Charlottesville, VA 22904, United States of America.
Jazyk: angličtina
Zdroj: Bioinspiration & biomimetics [Bioinspir Biomim] 2022 Nov 29; Vol. 18 (1). Date of Electronic Publication: 2022 Nov 29.
DOI: 10.1088/1748-3190/aca131
Abstrakt: When swimming near a solid planar boundary, bio-inspired propulsors can naturally equilibrate to certain distances from that boundary. How these equilibria are affected by asymmetric swimming kinematics is unknown. We present here a study of near-boundary pitching hydrofoils based on water channel experiments and potential flow simulations. We found that asymmetric pitch kinematics do affect near-boundary equilibria, resulting in the equilibria shifting either closer to or away from the planar boundary. The magnitude of the shift depends on whether the pitch kinematics have spatial asymmetry (e.g. a bias angle, θ 0 ) or temporal asymmetry (e.g. a stroke-speed ratio, τ ). Swimming at stable equilibrium requires less active control, while shifting the equilibrium closer to the boundary can result in higher thrust with no measurable change in propulsive efficiency. Our work reveals how asymmetric kinematics could be used to fine-tune a hydrofoil's interaction with a nearby boundary, and it offers a starting point for understanding how fish and birds use asymmetries to swim near substrates, water surfaces, and sidewalls.
(© 2022 IOP Publishing Ltd.)
Databáze: MEDLINE
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