Insects, birds, and bats that power and control flight by flapping their wings perform excellent flight stability and maneuverability by rapidly and continuously varying their wing motions. This article provides an overview of the state of the art of vortex-dominated, unsteady flapping aerodynamics from the viewpoint of diversity and uniformity associated with dominant vortices, particularly of the relevant physical aspects of the flight of insects and vertebrates in the low- and intermediate-Reynolds-number ( Re) regime of 100 to 106. After briefly describing wing morphology and kinematics, we discuss the main vortices generated by flapping wings and the aerodynamic forces associated with these structures, focusing on leading-edge vortices (LEVs), wake vortices, and vortices generated by wing motions over a broad Re range. The LEVs are intensified by dynamic wing morphing in bird and bat flight, producing a significantly elevated vortex lift. The complex wake vortices are the footprints of lift generation; thus, the time-averaged vortex lift can be estimated from wake velocity data. Computational fluid dynamics modeling, quasi-steady models, and vortex lift models are useful tools to elucidate the intrinsic relationships between the lift and the dominant vortices in the near- and far-fields in flapping flight.

中文翻译：

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生物飞行中的涡流和力：昆虫、鸟类和蝙蝠

通过拍打翅膀来驱动和控制飞行的昆虫、鸟类和蝙蝠通过快速、连续地改变翅膀运动来实现出色的飞行稳定性和机动性。本文从与主导涡流相关的多样性和均匀性角度，概述了涡流主导的非定常扑动空气动力学的最新技术，特别是低层和中层昆虫和脊椎动物飞行的相关物理方面。 -雷诺数 (Re) 范围为 100至 106。在简要描述机翼形态和运动学之后，我们讨论了扑动机翼产生的主要涡流以及与这些结构相关的气动力，重点关注前缘涡流 (LEV)、尾流涡流以及宽 Re 范围内机翼运动产生的涡流。鸟类和蝙蝠飞行时机翼的动态变形增强了 LEV，产生显着升高的涡升力。复杂的尾流涡流是升力产生的足迹；因此，可以根据尾流速度数据估计时间平均涡升力。计算流体动力学模型、准稳态模型和涡升力模型是阐明扑翼飞行中升力与近场和远场主要涡流之间内在关系的有用工具。