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Modulation of leading edge vorticity and aerodynamic forces in flexible flapping wings.
Bioinspir Biomim. 2011 Sep; 6(3):036007.BB

Abstract

In diverse biological flight systems, the leading edge vortex has been implicated as a flow feature of key importance in the generation of flight forces. Unlike fixed wings, flapping wings can translate at higher angles of attack without stalling because their leading edge vorticity is more stable than the corresponding fixed wing case. Hence, the leading edge vorticity has often been suggested as the primary determinant of the high forces generated by flapping wings. To test this hypothesis, it is necessary to modulate the size and strength of the leading edge vorticity independently of the gross kinematics while simultaneously monitoring the forces generated by the wing. In a recent study, we observed that forces generated by wings with flexible trailing margins showed a direct dependence on the flexural stiffness of the wing. Based on that study, we hypothesized that trailing edge flexion directly influences leading edge vorticity, and thereby the magnitude of aerodynamic forces on the flexible flapping wings. To test this hypothesis, we visualized the flows on wings of varying flexural stiffness using a custom 2D digital particle image velocimetry system, while simultaneously monitoring the magnitude of the aerodynamic forces. Our data show that as flexion decreases, the magnitude of the leading edge vorticity increases and enhances aerodynamic forces, thus confirming that the leading edge vortex is indeed a key feature for aerodynamic force generation in flapping flight. The data shown here thus support the hypothesis that camber influences instantaneous aerodynamic forces through modulation of the leading edge vorticity.

Authors+Show Affiliations

School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

21852729

Citation

Zhao, Liang, et al. "Modulation of Leading Edge Vorticity and Aerodynamic Forces in Flexible Flapping Wings." Bioinspiration & Biomimetics, vol. 6, no. 3, 2011, p. 036007.
Zhao L, Deng X, Sane SP. Modulation of leading edge vorticity and aerodynamic forces in flexible flapping wings. Bioinspir Biomim. 2011;6(3):036007.
Zhao, L., Deng, X., & Sane, S. P. (2011). Modulation of leading edge vorticity and aerodynamic forces in flexible flapping wings. Bioinspiration & Biomimetics, 6(3), 036007. https://doi.org/10.1088/1748-3182/6/3/036007
Zhao L, Deng X, Sane SP. Modulation of Leading Edge Vorticity and Aerodynamic Forces in Flexible Flapping Wings. Bioinspir Biomim. 2011;6(3):036007. PubMed PMID: 21852729.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Modulation of leading edge vorticity and aerodynamic forces in flexible flapping wings. AU - Zhao,Liang, AU - Deng,Xinyan, AU - Sane,Sanjay P, Y1 - 2011/08/19/ PY - 2011/8/20/entrez PY - 2011/8/20/pubmed PY - 2012/3/20/medline SP - 036007 EP - 036007 JF - Bioinspiration & biomimetics JO - Bioinspir Biomim VL - 6 IS - 3 N2 - In diverse biological flight systems, the leading edge vortex has been implicated as a flow feature of key importance in the generation of flight forces. Unlike fixed wings, flapping wings can translate at higher angles of attack without stalling because their leading edge vorticity is more stable than the corresponding fixed wing case. Hence, the leading edge vorticity has often been suggested as the primary determinant of the high forces generated by flapping wings. To test this hypothesis, it is necessary to modulate the size and strength of the leading edge vorticity independently of the gross kinematics while simultaneously monitoring the forces generated by the wing. In a recent study, we observed that forces generated by wings with flexible trailing margins showed a direct dependence on the flexural stiffness of the wing. Based on that study, we hypothesized that trailing edge flexion directly influences leading edge vorticity, and thereby the magnitude of aerodynamic forces on the flexible flapping wings. To test this hypothesis, we visualized the flows on wings of varying flexural stiffness using a custom 2D digital particle image velocimetry system, while simultaneously monitoring the magnitude of the aerodynamic forces. Our data show that as flexion decreases, the magnitude of the leading edge vorticity increases and enhances aerodynamic forces, thus confirming that the leading edge vortex is indeed a key feature for aerodynamic force generation in flapping flight. The data shown here thus support the hypothesis that camber influences instantaneous aerodynamic forces through modulation of the leading edge vorticity. SN - 1748-3190 UR - https://www.unboundmedicine.com/medline/citation/21852729/Modulation_of_leading_edge_vorticity_and_aerodynamic_forces_in_flexible_flapping_wings_ L2 - https://doi.org/10.1088/1748-3182/6/3/036007 DB - PRIME DP - Unbound Medicine ER -