褶皱位置对蜻蜓滑翔翼气动性能的影响

改变昆虫翅膀的褶皱结构可以优化翼型的气动性能，有利于微型飞行器的气动设计。以蜻蜓翼作为参考，采用计算流体力学（CFD）的方法计算了攻角范围为0°~20°，雷诺数范围为700~2300时褶皱位于前缘、尾缘和中部位置时三种翼型的滑翔气动性能。结果表明:在不同攻角和雷诺数下，褶皱位于尾缘的翼型具有最大的升力系数和升阻比，滑翔气动性能最优；当雷诺数为1500，攻角为10°时，褶皱位于尾缘的翼型时均升力系数分别比位于前缘和中部的翼型提高了58%和82%，升阻比分别提高了49%和33%；这是由于尾缘褶皱中的涡起到了延缓前缘涡脱落的作用，使前缘涡更为集中，更贴近壁面。 

Influence of corrugation position on aerodynamic performance of dragonfly gliding airfoils

The aerodynamic performance of airfoil can be optimized by changing the corrugation structure of insect wings, which can benefit the aerodynamic design of micro air vehicles. The gliding aerodynamic performances of three dragonfly-mimic airfoils, with corrugation located at the leading edge, trailing edge and middle position, were studied respectively by using computational fluid dynamics (CFD) method. The gliding angle of attack rose from 0° to 20°, and Reynolds number ranged from 700 to 2300. The results showed that the airfoil with the corrugation located at the trailing edge had the largest lift coefficient and lift-drag ratio at different angles of attack and Reynolds numbers, presenting the best gliding aerodynamic performance; when gliding at the angle of attack of 10° at Reynolds number of 1500, the time-averaged lift coefficient of the airfoil with the corrugation at the trailing edge was 58% and 82% larger than that of the airfoil with the corrugation at the leading edge and middle position, and the lift-drag ratio increased by 49% and 33%, respectively; the vortices in the corrugated trailing edge made the leading edge vortex more concentrated and closer to the wing surface, and delayed the shedding of the leading edge vortex.