Department of Mechanical Engineering, Defence Institute of Advanced Technology (DU), Girinagar, Pune 411025, Maharashtra, India.
Bioinspir Biomim. 2024 Jan 18;19(2). doi: 10.1088/1748-3190/ad1b2d.
The four-winged form of dragonfly and damselfly allows them to fly with great agility and endurance, which are accomplished by independently controlling the kinematics of each wing. In this study, we performed numerical simulations of two tandem airfoils oscillating along an inclined stroke plane atRe=157. We investigated the effects of the stroke plane angle (β)of forefoil and hindfoil on the aerodynamic performance of dragonflies (or damselflies) hovering flight. Simulations were conducted for parallel and non-parallel stroke planes of forefoil and hindfoil oscillating with three phase differences:ϕ=0o,90oand180o. For parallel stroke planes, the results show that the total lift increases withβ, whereas the total thrust decreases in same condition. In addition, the total lift and thrust decrease with an increase inϕ. The forefoil performance is affected by the flow induced by hindfoil's leading-edge vortices, and the hindfoil interactions with forefoil's wake vortices significantly affect the hindfoil's performance. The findings demonstrate that non-parallel stroke planes exert detrimental effects on the total lift forϕ=0oand90o. However, forϕ=180o, the lift augmentation of 46% is obtained in the case where the forefoil stroke plane angle is smaller than the hindfoil. The results obtained during this investigation can help in optimizing the wing kinematics during the micro air vehicles development.
蜻蜓和豆娘的四翼形式使它们能够以极高的敏捷性和耐力飞行，这是通过独立控制每个翅膀的运动学来实现的。在这项研究中，我们对两个串联翼型在 Re=157 下沿倾斜冲程平面进行了数值模拟。我们研究了前翼和后翼冲程平面角 (β)对蜻蜓（或豆娘）悬停飞行空气动力性能的影响。对于前翼和后翼以三个相位差 (ϕ=0o、90o 和 180o) 进行的平行和非平行冲程平面进行了模拟。对于平行冲程平面，结果表明总升力随β增加而增加，而在相同条件下总推力减小。此外，总升力和推力随ϕ 的增加而减小。前翼的性能受到后翼前缘涡的诱导流的影响，后翼与前翼尾迹涡的相互作用显著影响后翼的性能。研究结果表明，非平行冲程平面对ϕ=0o 和 90o 的总升力产生不利影响。然而，对于ϕ=180o，在前翼冲程平面角度小于后翼的情况下，可获得 46%的升力增强。本研究中获得的结果可以帮助优化微型飞行器开发过程中的机翼运动学。
