Fang Yan-Hung, Tang Chia-Hung, Lin You-Jun, Yeh Szu-I, Yang Jing-Tang
Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan.
Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701401, Taiwan.
Biomimetics (Basel). 2023 Jul 3;8(3):287. doi: 10.3390/biomimetics8030287.
This work investigates the effects of body angle and wing deformation on the lift of free-flying butterflies. The flight kinematics were recorded using three high-speed cameras, and particle-image velocimetry (PIV) was used to analyze the transient flow field around the butterfly. Parametric studies via numerical simulations were also conducted to examine the force generation of the wing by fixing different body angles and amplifying the chordwise deformation. The results show that appropriately amplifying chordwise deformation enhances wing performance due to an increase in the strength of the vortex and a more stabilized attached vortex. The wing undergoes a significant chordwise deformation, which can generate a larger lift coefficient than that with a higher body angle, resulting in a 14% increase compared to a lower chordwise deformation and body angle. This effect is due to the leading-edge vortex attached to the curved wing, which alters the force from horizontal to vertical. It, therefore, produces more efficient lift during flight. These findings reveal that the chordwise deformation of the wing and the body angle could increase the lift of the butterfly. This work was inspired by real butterfly flight, and the results could provide valuable knowledge about lift generation for designing microaerial vehicles.
这项研究调查了身体角度和翅膀变形对自由飞行蝴蝶升力的影响。使用三台高速摄像机记录飞行运动学，并采用粒子图像测速技术（PIV）分析蝴蝶周围的瞬态流场。还通过数值模拟进行了参数研究，通过固定不同的身体角度并放大弦向变形来研究翅膀的力产生情况。结果表明，适当放大弦向变形会由于涡旋强度的增加和附着涡旋的更稳定而提高翅膀性能。翅膀会经历显著的弦向变形，这可以产生比更高身体角度时更大的升力系数，与较低的弦向变形和身体角度相比，升力增加了14%。这种效果是由于附着在弯曲翅膀上的前缘涡旋将力从水平方向改变为垂直方向。因此，它在飞行过程中产生更有效的升力。这些发现表明，翅膀的弦向变形和身体角度可以增加蝴蝶的升力。这项工作受到真实蝴蝶飞行的启发，其结果可为设计微型飞行器的升力产生提供有价值的知识。
