仿生微型扑翼飞行器中的空气动力学问题研究进展与挑战

对仿生微型扑翼飞行器相关的空气动力学问题的研究进展进行了综述,并分析了未来发展面临的机遇与挑战。与自然界的飞行生物相比,目前仿生扑翼飞行器的飞行能力还很笨拙,距离高仿生还有较大距离。其中,所涉及的低雷诺数非定常空气动力学问题成为研究者在深入研究时面临的一个主要难题,关键在于数值模拟和风洞实验均难以准确模拟飞行中的实际状态。具体面临的难题主要包括:(1)仿生微型扑翼飞行器所处的雷诺数为103~105量级,属于对转捩与湍流非常敏感的区域,相关的气动机理复杂;(2)柔性翼在飞行中密切相关的动气动弹性问题;(3)高机动飞行导致的动气动弹性耦合飞行力学问题;(4)扑翼飞行的复杂姿态对飞控系统的挑战及反馈耦合算法的设计等。这些层层深入的多学科耦合难题导致了目前具备的研究手段难以为仿生扑翼飞行器的研究提供定量的分析与改进设计。在解决上述难题的基础上,未来可进一步在高机动灵活飞行姿态方面进行深入研究,对仿生柔性翼的刚度分布开展详细设计,使仿生扑翼飞行器具有像自然界飞行生物一样的主动变形能力,可在复杂的环境下具备高机动飞行能力,最终实现高仿生外形和性能的人造飞鸟或人造飞虫。

The progress and challenges of aerodynamics in the bionic flapping-wing micro air vehicle

The bionic micro air vehicle (MAV )has important applications in military and civilian usage.In recent years,researchers over the world have revealed several unique flight mechanisms ,and developed several kinds of bionic micro air vehicles capable of certain flight abil-ities.In this paper,the aerodynamics progress in the bionic MAV is reviewed;also,the opportu-nity and challenges faced in the future are analyzed.At present,compared with the natural flyers,manmade bionic MAV is still clumsy and in a lower level,and thus has a large room for improvement.Many problems need to be tackled.The aerodynamics of low Reynolds number flow in unsteady state is one of the main problems.Since the flow is complex in this regime,the numerical simulation and the wind tunnel experiment can hardly model the situation of true flight.There are four concrete problems:(1 )the Reynolds number of bionic MAV flows is around 103~105 .In this regime,the transition and turbulence are easy to turn up,which makes the flow mechanism complex;(2 )the dynamic aero-elastic problem of flexible wing MAV in flight.In this situation,the scaling law is hard when the size is different for the structure and flow has different reference value.It is an essential problem to establish an accurate simulating model;(3 )the coupling problem of aero-elasticity and flight dynamics in high maneuverable flight;(4)the influence of flight attitude of flapping wing on the flight control system increases the complexity of feedback coupling control algorithm.These multi-disciplinary coupling problems make it a challenge to provide high accurate analysis for and improve the design of the bionic MAV.In the future,by solving the above problems,the bionic MAV should have high maneuver ability and can morph actively,like the natural flyers.