【摘要】 大多数昆虫的拍翼运动由平动挥拍与俯仰旋转动组合而成。本文采用二维平板翼模型对悬停拍翼运动过程进行了模拟,翼型平动及转动速度满足简谐运动规律,并且上挥下拍过程对称。在保持挥拍中期攻角40度不变的情况下,改变俯仰速度或转动时间,采用DPIV(粒子速度成像仪)系统观测拍翼运动的流场涡结构,用测力天平测量模型翼升阻力的变化规律。实验结果表明,在转动阶段翼型升阻力的峰值随着转速的增大而增大,但整个拍翼周期内的平均升阻力变化不大;转速小时翼型升力的产生以攻角上仰升力机制为主,转速大时升力的产生以射流升力机制为主。更多还原

【Abstract】 The flapping-wing motion for most insects consists of plunging translation and pitching rotation.A two-dimensional planar foil model test system was employed to investigate the rotation effects of flapping wing motion in hovering flight.The translation and rotation speeds varied according to the rule of simple harmonic motion and the motion of the foil in one stroke circle was symmetric.The angle of attack during foil’s mid-stroke was kept constant(α_m=40°),and only the speed or duration of pitching rotation was changed.The visualization of vortex field was carried out by using a DPIV(Digital Particle Image Velocimetry) system,and the aerodynamic force of the foil was measured with a force balance.It was found that the larger the speed of pitching rotation,the more easily the leading edge vortex attaches to the foil.The peak of the lift or drag curve at the beginning of a stroke is higher when the rotational speed is larger,but the average lift or drag in one stroke cycle changes little.更多还原