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蜻蜓等昆虫作为飞行领域的佼佼者具有优异的机动性能,然而基于仿生学研制的微型扑翼飞行器在机动性能方面却远不如昆虫。为研究昆虫机动飞行时的气动特性,本文采用有限体积法对蜻蜓左右两侧翅膀非对称扑动时的三维气动力及力矩进行了数值计算,并对不同扑动幅值下蜻蜓的整体气动性能以及每一个翅膀的气动性能、压力分布及流场结构进行了系统分析。结果表明:仅需增加某侧两翅的扑动幅值即可实现向另一侧的机动飞行;相比后翅,扑动幅值对前翅的升推力、滚转及偏航力矩影响较大,而对侧向力的影响较小;扑动幅值对翅膀的瞬时阻力、侧向力、偏航及俯仰力矩在整个扑动周期内均产生了明显影响,而对瞬时升力和滚转力矩的影响则集中在下扑阶段;扑动幅值改变了翅膀前缘涡、尾涡的强度及上下表面的压力差,在下扑阶段,翅膀和蜻蜓对称面有个相对倾角,气动合力产生了较大的侧向力,而上扑阶段,翅膀几乎垂直对称面,产生的侧向力较小。以上结果对于仿生扑翼飞行器的控制及气动设计具有一定指导意义。
Dragonflies and other insects as a leader in the field of flying have excellent maneuverability, however, based on the bionic micro flapping wing aircraft maneuver performance is far inferior to insects. In order to study the aerodynamic characteristics of insect flight, the finite volume method was used to calculate the three-dimensional aerodynamic forces and moments during the asymmetrical flutter of the left and right dragonflies. The aerodynamic performance of the dragonfly under different flutter amplitudes And the aerodynamic performance, pressure distribution and flow field structure of each wing were systematically analyzed. The results show that the maneuver flight to the other side can be realized only by increasing the flutter amplitude of two wings on one side. Compared with the hind wings, the amplitude of flutter affects the lift, roll and yaw moment of the forewing wing significantly , While the impact on lateral force is small. The instantaneous drag, lateral force, yaw and pitch moment of flutter amplitude have a significant impact on the entire flutter cycle, while the instantaneous lift and roll torque The flutter amplitude changes the leading edge eddy and caudal vortex strength and the pressure difference between the upper and lower surfaces. At the bottom flutter phase, there is a relative dip between the wings and the symmetry plane of the dragonfly, and the resultant aerodynamic force is larger Of the lateral force, while the upper stage, wings almost vertical symmetry plane, the resulting lateral force is smaller. The above results have certain guiding significance for the control and aerodynamic design of bionic flapping-wing aircraft.