Aerodynamic performance and mechanism for a flexible membrane wing encountering a harmonic transverse gust

IF 2.3 3区工程技术 Q2 ENGINEERING, MECHANICAL

Experiments in Fluids Pub Date : 2025-02-07 DOI:10.1007/s00348-025-03966-6

Xi He, Siyuan Feng, Qinfeng Guo, Jinjun Wang

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Abstract

To assess the performance of a flexible membrane wing in a harmonic transverse gust, the aerodynamic forces, membrane deformations and surrounding flow fields are synchronously measured. The gust is generated by two periodically pitching airfoils. First, the flexible wing outperforms its rigid counterparts in time-averaged lift, achieving a maximum lift increment of 44.6% at the angle of attack (α) of 16°. The lift-enhancement is attributed to the camber increase and membrane vibration to suppress flow separation—a mechanism analogous to the behavior in steady flow conditions. Second, for the unsteady lift response, the flexible and rigid cambered wings reduce lift fluctuations induced by the gust when 3° ≤ α ≤ 9°, implying a gust alleviation effect. The maximum alleviation of the flexible wing is 32.0% at α = 6°. To elucidate the gust alleviation mechanism, phase-averaged lift and flow fields at α = 6° are investigated. The flow over the flexible wing remains consistently attached, while the rigid plate wing exhibits the evolution of leading-edge vortices (LEVs). These LEVs provide additional lift that helps the rigid plate wing to match the maximum lift of the flexible wing. However, the minimum lift of the plate wing is much smaller. Consequently, the primary reason for the aerodynamic load alleviation is elaborated. However, the inherent resonant vibration of the membrane is a by-product that has a negative impact on the alleviation effect.

Graphical abstract

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柔性膜翼遇到谐波横向阵风的气动性能及机理

为了评估柔性膜翼在谐波横向阵风中的性能，同步测量了气动力、膜变形和周围流场。阵风是由两个周期性俯仰翼型产生的。首先，柔性翼在时间平均升力方面优于刚性翼，在攻角（α）为16°时，最大升力增量为44.6%。升力的增加是由于弯曲度的增加和膜的振动抑制了流动分离，这一机制类似于稳定流动条件下的行为。②对于非定常升力响应，当3°≤α≤9°时，柔性和刚性弧形机翼均能减小阵风引起的升力波动，具有缓解阵风的作用；当α = 6°时，柔性翼的最大缓和度为32.0%。为了阐明阵风缓解机制，研究了α = 6°时的相平均升力和流场。柔性翼上的气流始终保持附着，而刚性板翼则表现出前缘涡的演变。这些lev提供额外的升力，帮助刚性板机翼匹配柔性机翼的最大升力。然而，板翼的最小升力要小得多。因此，阐述了气动载荷减轻的主要原因。然而，膜固有的共振振动是一种副产物，对缓解效果有负面影响。图形抽象

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Experiments in Fluids 工程技术-工程：机械

CiteScore

5.10

自引率

12.50%

发文量

157

审稿时长

3.8 months

期刊介绍： Experiments in Fluids examines the advancement, extension, and improvement of new techniques of flow measurement. The journal also publishes contributions that employ existing experimental techniques to gain an understanding of the underlying flow physics in the areas of turbulence, aerodynamics, hydrodynamics, convective heat transfer, combustion, turbomachinery, multi-phase flows, and chemical, biological and geological flows. In addition, readers will find papers that report on investigations combining experimental and analytical/numerical approaches.