Enhanced flight performance in non-uniformly flexible wings
Enhanced flight performance in non-uniformly flexible wings
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DOI：
10.1098/rsif.2020.0352
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发表时间：
2020-04
影响因子：
3.9
通讯作者：
L. Vincent;Min Zheng;J. Costello;E. Kanso
中科院分区：
文献类型：
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作者：
L. Vincent;Min Zheng;J. Costello;E. Kanso
生物推进器的灵活性，如翅膀和鳍，被认为有助于飞行和游泳动物比它们的工程同行更好的表现。柔韧性似乎遵循一个普遍的设计规则，即在推进器跨度的远端约三分之一处诱导弯曲图案。然而，形成这种融合设计的空气动力学机制和性能的潜在改进并不是很清楚。本文分析了非均匀柔度对被动翻转机翼飞行性能(航程和下降角)的影响。通过实验、数值模拟和比例分析，我们证明了遵循这一经验规则的跨距叶尖灵活性可以改善飞行性能。飞行距离的改善似乎与颤振引起的减阻有关。这种机构与机翼的自动旋转无关，并且代表了具有非均匀尖端灵活性的机翼的更一般特征。
The flexibility of biological propulsors such as wings and fins is believed to contribute to the higher performance of flying and swimming animals compared with their engineered peers. Flexibility seems to follow a universal design rule that induces bending patterns at about one-third from the distal tip of the propulsor’s span. However, the aerodynamic mechanisms that shaped this convergent design and the potential improvement in performance are not well understood. Here, we analyse the effect of heterogeneous flexibility on the flight performance (range and descent angle) of passively tumbling wings. Using experiments, numerical simulations, and scaling analysis, we demonstrate that spanwise tip flexibility that follows this empirical rule leads to improved flight performance. Improvement in flight range seems to be related to flutter-induced drag reduction. This mechanism is independent of the wing’s auto-rotation and represents a more general trait of wings with non-uniform tip flexibility.