Structure and Motional Laboratory, Royal Veterinary College, Hatfield AL9 7TA, UK.
Department of Aerospace Engineering, University of Bristol, Bristol BS8 1TR, UK.
J R Soc Interface. 2021 Jul;18(180):20210349. doi: 10.1098/rsif.2021.0349. Epub 2021 Jul 14.
In gliding flight, birds morph their wings and tails to control their flight trajectory and speed. Using high-resolution videogrammetry, we reconstructed accurate and detailed three-dimensional geometries of gliding flights for three raptors (barn owl, ; tawny owl, , and goshawk, ). Wing shapes were highly repeatable and shoulder actuation was a key component of reconfiguring the overall planform and controlling angle of attack. The three birds shared common spanwise patterns of wing twist, an inverse relationship between twist and peak camber, and held their wings depressed below their shoulder in an anhedral configuration. With increased speed, all three birds tended to reduce camber throughout the wing, and their wings bent in a saddle-shape pattern. A number of morphing features suggest that the coordinated movements of the wing and tail support efficient flight, and that the tail may act to modulate wing camber through indirect aeroelastic control.
在滑翔飞行中,鸟类会改变翅膀和尾巴的形状来控制飞行轨迹和速度。我们使用高分辨率运动图像测量技术,为三种猛禽(仓鸮、;长耳鸮和游隼)重建了准确而详细的滑翔飞行三维几何形状。翅膀形状高度可重复,肩部运动是改变整体翼型和控制迎角的关键组成部分。这三种鸟的翅膀扭转具有共同的展向模式,扭转与峰值弯度之间存在反比关系,并且它们的翅膀在肩部下方呈下反角配置。随着速度的增加,这三种鸟在整个机翼上的弯度都趋于减小,并且它们的翅膀呈鞍形弯曲。许多变形特征表明,翅膀和尾巴的协调运动支持高效飞行,并且尾巴可能通过间接空气弹性控制来调节机翼的弯度。