Wing/body kinematics measurement and force and moment analyses of the takeoff flight of fruitflies
In the paper, we present a detailed analysis of the takeoff mechanics of fruitflies which perform voluntary takeoff flights. Wing and body kinematics of the insects during takeoff were measured using high-speed video techniques. Based on the measured data, inertia force acting on the insect was computed and aerodynamic force and moment of the wings were calculated by the method of computational fluid dynamics. Subtracting the aerodynamic force and the weight from the inertia force gave the leg force. The following has been shown. In its voluntary takeoff, a fruitfly jumps during the first wingbeat and becomes airborne at the end of the first wingbeat. When it is in the air, the fly has a relatively large “initial” pitch-up rotational velocity (more than 5 000°/s) resulting from the jumping, but in about 5 wing-beats, the pitch-up rotation is stopped and the fly goes into a quasi-hovering flight. The fly mainly uses the force of jumping legs to lift itself into the air (the force from the flapping wings during the jumping is only about 5%–10% of the leg force). The main role played by the flapping wings in the takeoff is to produce a pitch-down moment to nullify the large “initial” pitch-up rotational velocity (otherwise, the fly would have kept pitching-up and quickly fallen down).
KeywordsFruitfly Takeoff flight Body and wing kinematics Aerodynamic and leg forces
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- 6.Sunada, S., Kawachi, K., Watanabe, I., et al: Performance of a butterfly in take-off flight. J. Exp. Biol. 183, 249–277 (1993)Google Scholar
- 7.Weis-Fogh, T.: Quick estimates of flight fitness in hovering animals, including novel mechanisms for lift production. J. Exp. Biol. 59, 169–230 (1973)Google Scholar
- 17.Rogers, S.E., Pulliam, T.H.: Accuracy enhancements for overset grids using a defect correction approach. AIAA Paper No. 94-0523 (1994)Google Scholar
- 23.Togashi, F., Yasushi, I., Mitsuhiro, M., et al: Flow simulation of flapping wings of an insect using overset unstructured grid. AIAA Paper No. 2001-261 (2001)Google Scholar
- 24.Hilgenstock, A.: A fast method for the elliptic generation of three dimensional grids with full boundary control. In: Num. Grid Generation in CFM’88 (Sengupta, S., Hauser, J., Eiseman, P.R., Thompson, J.F. edn.), Pineridge Press Ld, Swansea UK 137–146 (1988)Google Scholar