Collaborative Research: Aerodynamic-aeroacoustic performance of poroelastic wings inspired by the silent plumage of owls

合作研究：受猫头鹰沉默羽毛启发的多孔弹性机翼的空气动力-气动声学性能

• 批准号: 1804445
• 负责人: Michael Krane
• 金额: $ 27.04万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-06-15 至 2022-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1804445&HistoricalAwards=false
• 关键词: Collaborative; Research; Aerodynamic; aeroacoustic; performance

Owls are extraordinary predators that are able to suppress their aerodynamic noise generation and achieve effectively silent flight over a broad frequency range, which includes the sensitive hearing ranges of owls, their prey, and humans. The poroelastic fringe adaptation of owls is believed to contribute to this broadband noise suppression by modifying the trailing-edge noise mechanism that sets the minimum noise level of many engineering designs, such as computer fans, propulsors, commercial airframes, and wind turbines. Many applications for which weaker edge noise is sought are also constrained by, for example, aerodynamic performance or stability metrics related to the integrated pressure across these fluid-loaded structures (e.g., lift or moment). Furthermore, it is clear that changes to the trailing-edge geometry and compliance to improve acoustic performance should entail an aerodynamic performance penalty. In this scenario, the unsteady acoustic and hydrodynamic fields must be considered together. At present, guidance towards a more complete understanding of their interaction for finite-chord and finite-span structures with variable porous and elastic properties is lacking. Furthermore, there is little empirical support for the predicted aerodynamic and aeroacoustic effects of poroelastic edges. The principal aim of this project is to address these shortcomings through a series of analytical and numerical model problems coordinated with experimental measurement to elucidate the unsteady loading and noise generation of thin fluid-loaded structures with graded poroelastic properties. This project addresses the above technical shortcomings through an interactive theoretical-experimental program that distinguishes itself in no fewer than three ways: (i) construction of analytical and numerical frameworks to predict turbulence noise generation by graded poroelastic structures, from first principles; (ii) experimental validation of acoustic scaling laws for poroelastic edges, without background flow noise; and (iii) development of a glider to measure wing noise on the fly in a manner consistent with how owls hear their self-noise. The modeling and validation efforts aim to transform a biologically-inspired noise solution into a rational paradigm for passive aerodynamic noise control in low-speed flows and to create an experimental platform for future bionic owl noise-reduction studies. This project will also include K-12 educational outreach with the DaVinci Science Center (Allentown, PA), as well as integrate undergraduate research involvement through the Lehigh Biosystems Dynamics Summer Institute (in partnership with Northampton Community College) and through a design-build-fly competition between Lehigh and Penn State.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

猫头鹰是一种非同寻常的捕食者，能够抑制它们产生的空气动力学噪音，并在包括猫头鹰、猎物和人类的敏感听力范围在内的广泛频率范围内实现有效的无声飞行。OWLS的多孔弹性条纹自适应被认为是通过修改后缘噪声机制来促进这种宽带噪声抑制的，该机制设置了许多工程设计的最低噪声水平，例如计算机风扇、推进器、商用机身和风力涡轮机。寻求较弱边缘噪声的许多应用还受到例如与这些流体加载结构上的积分压力(例如，升力或力矩)有关的空气动力学性能或稳定性度量的限制。此外，很明显，改变后缘的几何形状和顺应性来改善声学性能应该会导致气动性能的损失。在这种情况下，必须同时考虑非定常声场和流体动力场。目前，对于具有可变孔洞和弹性性质的有限弦杆和有限跨度结构，缺乏对它们相互作用的更全面理解的指导。此外，预测的孔弹边缘的空气动力学和气动声学效应几乎没有经验支持。这个项目的主要目的是通过一系列的分析和数值模型问题结合实验测量来解决这些缺点，以阐明具有梯度孔弹性性质的薄壁流体加载结构的非定常载荷和噪声产生。该项目通过一个互动式的理论-实验计划解决上述技术缺陷，该计划至少在三个方面有所不同：(1)从基本原理出发，构建分析和数值框架，以预测分级孔弹性结构产生的湍流噪声；(2)在没有背景流动噪声的情况下，对孔弹性边的声学标度定律进行实验验证；(3)开发一种滑翔机，以与猫头鹰听到自身噪声的方式一致的方式，在飞行中测量机翼噪声。建模和验证工作旨在将受生物启发的噪声解决方案转变为低速流动中被动空气动力噪声控制的合理范例，并为未来的仿生猫头鹰降噪研究创建一个实验平台。该项目还将包括与达芬奇科学中心(宾夕法尼亚州阿伦敦市)的K-12教育拓展，以及通过利哈伊生物系统动力学暑期研究所(与北安普顿社区学院合作)以及利哈伊和宾夕法尼亚州立大学之间的设计-建造-飞行竞赛来整合本科生研究参与。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。