In this study, experimental investigation is performed into modification to aerodynamic characteristics by distortion and vibration of planar wings with various Young’s modulus as well as flow fields around them. Motions of the wings are captured with a high-speed camera. Flows around them are evaluated with phase locked PIV technique. As a result, bending vibration of the wings is observed almost all over the angles of attack while twisting is observed around the angles giving maximum lift force. The twisting vibration causes larger aerodynamic forces and delay in the stall. It is found that amplitude of the twisting determines magnitude of variations in aerodynamic forces. Flow field measurement shows the twisting vibration generates periodic vortices shedding from the leading and trailing edges. They reduce the separation bubble on the wing, in particular, around the middle span in spite of localization of the twisting in the vicinity of the wing tip.
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The author would like to acknowledge the support of Mr. T. Toshijima, who was a postgraduate student of Toyota Technological Institute, to execute these experiments.
Kolomenskiy, D., Engels, T., Schneider, K.: Numerical modeling of flexible heaving foils. J. Aero Aqua Bio-Mech. 3(1), 22–28 (2013)CrossRefGoogle Scholar
Michelin, S., Smith, S.G.L.: Resonance and propulsion performance of a heaving flexible wing. Phys. Fluids 21, 071902 (2009)CrossRefzbMATHGoogle Scholar
Kurinami, T., Fuchiwaki, M., Tanaka, K.: Vortex flow developed in the vicinity of a wall of an elastic heaving airfoils and its wake structure. J. Fluid Sci. Technol. 6 (4), 562–574 (2011)CrossRefGoogle Scholar
Unger, R., Haupt, M.C., Horst, P., Radespiel, R.: Fluid-structure analysis of a flexible flapping airfoil at low Reynolds number flow. J. Fluids Struct. 28, 72–88 (2012)CrossRefGoogle Scholar
DeLuca, A.M., Reeder, M.F., Freeman, J., Ol, M.V.: Flexible- and rigid- wing micro air vehicle: lift and drag comparison. J. Aircraft 43(2), 572–575 (2006)CrossRefGoogle Scholar
Albertani, R., Stanford, B., Hubner, J.P., Ifju, P.G.: Aerodynamic coefficients and deformation measurements on flexible micro air vehicle wings. Exp. Mech. 47, 625–635 (2007)CrossRefGoogle Scholar
Ramananarivo, S., Godoy-Diana, R., Thiria, B.: Rather than resonance, flapping wing flyers may play on aerodynamics to improve performance. Proc. Natl. Acad. Sci. 108(15), 5964–5969 (2011)CrossRefGoogle Scholar
Lua, K.B., Lai, K.C., Lim, T.T., Yeo, K.S.: On the aerodynamic characteristics of hovering rigid and flexible hawkmoth-like wings. Exp. Fluids 49, 1263–1291 (2010)CrossRefGoogle Scholar
Ren, H., Wu, Y., Huang, P.G.: Visualization and characterization of near-wake flow fields of a flapping-wing micro air vehicle using PIV. J. Vis. 16, 75–83 (2103)CrossRefGoogle Scholar
Isogai, K.: Effect of flexibility of the caudal fin on the propulsive performance of dolphins. Trans. Jpn. Soc. Aero. Space Sci. 57(1), 21–30 (2014)CrossRefGoogle Scholar