Distributed feather-inspired flow control mitigates stall and expands flight envelope.

Autor:	Sedky G; Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544., Simon N; Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544., Othman AK; Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544., Wiswell H; Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544., Wissa A; Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2024 Nov 05; Vol. 121 (45), pp. e2409268121. Date of Electronic Publication: 2024 Oct 28.
DOI:	10.1073/pnas.2409268121
Abstrakt:	Multiple rows of feathers, known as the covert feathers, contour the upper and lower surfaces of bird wings. These feathers have been observed to deploy passively during high angle of attack maneuvers and are suggested to play an aerodynamic role. However, there have been limited attempts to capture their underlying flow physics or assess the function of multiple covert rows. Here, we first identify two flow control mechanisms associated with a single covert-inspired flap and their location sensitivity: a pressure dam mechanism and a previously unidentified shear layer interaction mechanism. We then investigate the additivity of these mechanisms by deploying multiple rows of flaps. We find that aerodynamic benefits conferred by the shear layer interaction are additive, whereas benefits conferred by the pressure dam effect are not. Nevertheless, both mechanisms can be exploited simultaneously to maximize aerodynamic benefits and mitigate stall. In addition to wind tunnel experiments, we implement multiple rows of covert-inspired flaps on a bird-scale remote-controlled aircraft. Flight tests reveal passive deployment trends similar to those observed in bird flight and comparable aerodynamic benefits to wind tunnel experiments. These results indicate that we can enhance aircraft controllability using covert-inspired flaps and form insights into the aerodynamic role of covert feathers in avian flight. Competing Interests: Competing interests statement:The authors declare no competing interest.
Databáze:	MEDLINE
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