蜻蜓爬升过程飞行特征实验研究

昆虫真实飞行过程中的飞行特征是仿生流体力学机理研究的基础和关键。本文针对蜻蜓(黄蜻)大、小爬升角2种飞行状态的运动规律和动力学特性展开研究,根据蜻蜓的趋光特性诱导其进行爬升飞行。采用2台光轴相互垂直的高速摄像机进行拍摄,通过特征点匹配和三维重构方法准确地捕捉了2种爬升飞行过程中蜻蜓身体和翅膀的运动参数,并进行动力学特性对比分析。实验结果表明:蜻蜓在进行大爬升角爬升时需要的上升力大于向前的推力,最大拍动幅度比小爬升角爬升时约大40%;扑翼频率比小爬升角爬升时约大3.3 Hz,前后翅相位差相对于小爬升角爬升时减小20°以上;另外,大爬升角爬升过程中前翅前倾角度更大,这样能够使蜻蜓身体保持更大的俯仰角,翅膀能够获得更大的上升力。

Experimental study on flight performance of dragonfly during climbing

The flight performances of insects in free flight are very important for the research of the bionic fluid mechanics. The movement law and dynamic characteristics of dragonfly Pantala flavescens during climbing flight in two different flying angles are investigated using high-speed videography. We induced the dragonfly climbing according to the phototaxis of the fliers. Two high-speed cameras with orthogonal axes are used. The body and wings kinematics of dragonflies are captured accurately by feature points matching and three-dimensional reconstruction and the flight performance is studied. The experimental results show that the lift of the flier is lager than the thrust during high-incidence climbing and maximum flapping amplitude of the dragonfly during high-incidence climbing is 40% bigger than that during low-incidence climbing; the flapping frequency of high-incidence climbing is 3.3 Hz more than that of low-incidence climbing and the phase difference of high-incidence climbing is 20° smaller than that of the other. The pitch angle of the body during high-incidence climbing is larger than normal, which is controlled by the front inclination angle of forewing. This body attitude can generate larger lift force.