Effects of cambers on gliding and hovering performance of corrugated dragonfly airfoils
International Journal of Numerical Methods for Heat & Fluid Flow
ISSN: 0961-5539
Article publication date: 3 May 2016
Abstract
Purpose
The purpose of this paper is to explore the effects of the camber on gliding and hovering performance of two-dimensional corrugated airfoils. While the flying mechanism of natural flyers remains a myth up to nowadays, the simulation serves as a minor step toward understanding the steady and unsteady aerodynamics of the dragonfly flight.
Design/methodology/approach
The lattice Boltzmann method is used to simulate the flow past the cambered corrugated dragonfly airfoil at low Reynolds numbers. For gliding flight, the maximum camber, the distance of the location of maximum camber point from the leading edge and Reynolds number are regarded as control variables; for hovering flight, the maximum camber, the flapping amplitude and trajectory are considered as control variables. Then corresponding simulations are performed to evaluate the implications of these factors.
Findings
Greater gliding ratio can be reached by increasing the maximum camber of the dragonfly wing section. When the location of the maximum camber moves backward along the wing chord, large scale flow separation can be delayed. These two effects result in better gliding performances. For hovering performances, it is found that for different flapping amplitudes along an inclined plane, the horizontal force exerted on the airfoils increases with the camber, and the drag growths first but then drops. It is also found that the elliptic flapping trajectory is most sensitive to the camber of the cambered corrugated dragonfly wing section.
Originality/value
The effects of the camber on gliding and hovering performance of the cambered dragonfly wing section are explored in detail. The data obtained can be helpful when designing micro aerial vehicles.
Keywords
Acknowledgements
The authors wish to thank the National Natural Science Foundation of China (Grant No. 11372278). The authors would like to thank the Center for Engineering and Scientific Computation, Zhejiang University, for its computational resources, with which the research project has been carried out.
Citation
Shi, X., Huang, X., Zheng, Y. and Zhao, S. (2016), "Effects of cambers on gliding and hovering performance of corrugated dragonfly airfoils", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 26 No. 3/4, pp. 1092-1120. https://doi.org/10.1108/HFF-10-2015-0414
Publisher
:Emerald Group Publishing Limited
Copyright © 2016, Emerald Group Publishing Limited