拍动的鸟类翅膀如何展现出优异的空气动力学性能？

中文摘要 AI 辅助

本研究使用自主开发的尖锐界面浸入边界求解器VorteXdyn，探究受鸟类启发的拍动翅膀的非定常空气动力学性能与涡动力学。采用基于NACA 4312翼型的隼启发的体-翼模型，在雷诺数为2500、5000和10000，斯特劳哈尔数为0.18、0.225和0.27的稳态前飞拍动飞行过程中，研究空气动力产生与涡演化。通过三种翼构型探究生理结构的影响：无明显羽毛结构的简化翼、后缘带有羽毛状结构（锯齿）的翼、翼展方向包含初级、次级和中央羽毛多层结构的几何细节翼。利用升力系数、阻力系数及升阻比的时间剖面与时均特性，量化这些构型的空气动力学性能；通过多个前缘涡（LEV）的形成与演化、展向相干性、环量、特征尺寸及在翼面的持续时间，表征相关涡动力学。特别关注下拍过程中LEV从翼根到翼尖的展向发展、其与翼尖涡的相互作用及产生的尾流演化。结果表明，提高几何保真度会改变空气动力产生、多个LEV结构的形成与演化、涡-涡及涡-翼相互作用、尾流拓扑。这些发现为三维拍动飞行中羽毛形态的空气动力学作用提供了认识，也为高效仿生扑翼微型飞行器的空气动力学设计提供了依据。

英文摘要

This work investigates the unsteady aerodynamic performance and vortex dynamics of avian-inspired flapping wings using our in-house sharp-interface immersed-boundary solver, VorteXdyn. A falcon-inspired body-wing model based on NACA 4312 profile is employed to examine aerodynamic force generation and vortex evolution during steady forward flapping flight at Reynolds numbers of 2,500, 5000, and 10000 and Strouhal numbers of 0.18, 0.225, and 0.27. The influence of physiologies is examined using three wing configurations: a simplified wing without distinct feather structures, a wing incorporating feather-like structures (serrations) along the trailing edge, and a geometrically detailed wing incorporating multiple feather layers consisting of primary, secondary, and median feathers over its span. The aerodynamic performance of these configurations is quantified using the temporal profiles and time-averaged characteristics of the lift and drag coefficients and the lift-to-drag ratio. The associated vortex dynamics are characterized through the formation and evolution of multiple leading-edge vortices (LEVs), their spanwise coherence, circulation, characteristic size, and persistence over the wings' surfaces. Particular emphasis is placed on the spanwise development of the LEVs from the root to the wingtip, their interactions with the tip vortices, and the resulting wake evolution during the downstroke. Our results demonstrate that increasing geometric fidelity modifies aerodynamic force production, the formation and evolution of multiple LEV structures, vortex-vortex and votex-wing interactions, and wake topology. These findings provide insight into the aerodynamic role of feather morphology in three-dimensional flapping flight for the aerodynamic design of efficient bio-inspired flapping-wing micro air vehicles.

发表机构

• Lakehead University（湖首大学）

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