Department of Mechanical Engineering, National Taiwan University, Taipei, Taiwan.
Bioinspir Biomim. 2020 Dec 9;16(1). doi: 10.1088/1748-3190/abc293.
We investigated the effect of the wing-wing interaction, which is one key aspect of flight control, of damselflies (and) in forward flight that relates closely to their body morphologies and wing kinematics. We used two high-speed cameras aligned orthogonally to measure the flight motions and adopted 3D numerical simulation to analyze the flow structures and aerodynamic efficiencies. The results clarify the effects of wing-wing interactions, which are complicated combinations of biological morphology, wing kinematics and fluid dynamics. As the amplitude of the hindwing ofis larger than that of, the effect of the wing-wing interaction is more constructive. Restricted by the body morphology of, the flapping range of the hindwing is below the body. With the forewing in the lead, the hindwing is farther from the forewing, which is not susceptible to the wake of the forewing, and enables superior lift and thrust. Because of the varied rotational motions, the different shed direction of the wakes of the forewings causes the optimal thrust to occur in different wing phases. Because of its biological limitations, a damselfly can use an appropriate phase to fulfill the desired flight mode. The wing-wing interaction is a compromise between lift efficiency and thrust efficiency. The results reveal that a damselfly with the forewing in the lead can have an effective aerodynamic performance in flight. As an application, in the design concept of a micro-aircraft, increasing the amplitude of the hindwing might enhance the wing-wing interaction, thus controlling the flight modes.
我们研究了蜻蜓在向前飞行时的翅膀相互作用，这是飞行控制的一个关键方面，与它们的身体形态和翅膀运动学密切相关。我们使用两个正交对齐的高速摄像机来测量飞行运动，并采用 3D 数值模拟来分析流场结构和空气动力学效率。结果阐明了翅膀相互作用的影响，这些影响是生物形态、翅膀运动学和流体动力学的复杂组合。由于后翅的振幅大于前翅，因此翅膀相互作用的效果更具建设性。由于的身体形态的限制，后翅的拍打范围低于身体。在前翅的引领下，后翅离前翅更远，不容易受到前翅尾流的影响，从而能够提供更好的升力和推力。由于不同的旋转运动，前翅尾流的不同释放方向导致最佳推力出现在不同的机翼相位。由于其生物限制，蜻蜓可以利用适当的相位来实现所需的飞行模式。翅膀相互作用是升力效率和推力效率之间的妥协。结果表明，在前翅领先的蜻蜓在飞行中可以具有有效的空气动力性能。作为一种应用，在微型飞行器的设计概念中，增加后翅的振幅可能会增强翅膀相互作用，从而控制飞行模式。
