Understanding and developing new noise reduction mechanisms for aerofoils in unsteady flow through the use of analytical mathematics

通过使用分析数学来理解和开发非定常流中机翼的新降噪机制

• 批准号: EP/P015980/1
• 负责人: Lorna Ayton
• 金额: $ 77.09万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FP015980%2F1
• 关键词: Understanding; developing; new; noise; reduction

This project centres on finding mathematical solutions to complicated fluid-structure interaction problems, bringing together a variety of advanced mathematical techniques to solve key problems in the aerospace industry, such as reducing aircraft noise. Excessive environmental noise from airports and wind farms is a key issue affecting both public health and the expansion of the aviation and sustainable energy industries.A current expanding area of research in aeroacoustics is in leading-edge (at the front) and trailing-edge (at the rear) adaptations to standard blades on aeroplanes or wind turbines. It is believed that these adaptations can lead to significant decreases in generated noise and are largely inspired by nature, in particular the silent flight of owls. It is well known that owls are unique among birds in that they fly almost silently. This is believed to be possible due to a number of features their wings possess which are not present in other species. By creating new designs aimed at mimicking these owl-like features, this project shall attempt to significantly reduce noise generated by aircraft and wind turbine blades.A primary source of noise generated by aeroengine blades is leading-edge noise, arising from the interaction of an unsteady fluid with the front of the solid body. Conversely, trailing-edge noise is a dominant contributor to airframe and wind turbine noise, arising due to the interaction of turbulence above the blades with the rear of the blade (the trailing edge).Understanding and quantifying the mechanisms generating these different types of noise is vital to knowing what adaptations can be made to current designs in order to reduce the overall sound emitted by these systems. Potential noise reduction designs include; blades with serrated, or porous and flexible trailing edges, or fringed leading edges. Research into the effectiveness of these designs is typically experimental or numerical, which cannot delve deeper in to the results to tell you why such a design is effective, merely if it is or not. This project ultimately aims to provide the answer to why. Mathematical solutions derived using analytic methods can be incredibly powerful as they preserve the vital physics of these fluid-structure interaction problems, but significantly reduce computational costs and can address cases in which numerical models struggle, such as generation of high-frequency noise. The speed of mathematical predictions can identify important areas that require further investigation, giving a head start to developing new noise-reducing or increased-performance technologies.Through mathematical analysis, this project will give insight into the mechanisms by which these adapted leading- and trailing-edge designs reduce noise, and obtain relationships between key design features, such as the porosity of a trailing-edge adaptation or original blade geometry, and the total noise reduction, allowing for quick optimisation of the design without the need for large numbers of experiments or costly computation.

该项目的重点是寻找复杂的流体-结构相互作用问题的数学解决方案，汇集各种先进的数学技术来解决航空航天工业中的关键问题，例如降低飞机噪音。来自机场和风力发电场的过量环境噪声是影响公共健康以及航空和可持续能源工业发展的关键问题。目前航空声学研究的一个扩展领域是对飞机或风力涡轮机上标准叶片的前缘（在前部）和后缘（在后部）的适应。据信，这些适应可以导致产生的噪音显着减少，并在很大程度上受到自然的启发，特别是猫头鹰的无声飞行。众所周知，猫头鹰在鸟类中是独一无二的，因为它们几乎无声地飞行。这被认为是可能的，因为它们的翅膀具有许多其他物种所不具备的特征。通过创建旨在模仿这些猫头鹰状特征的新设计，该项目将尝试显着降低飞机和风力涡轮机叶片产生的噪音。航空发动机叶片产生的噪音的主要来源是前缘噪音，由不稳定流体与固体前部的相互作用产生。相反，后缘噪声是机体和风力涡轮机噪声的主要贡献者，由于叶片上方的湍流与叶片后部（后缘）的相互作用而产生。理解和量化产生这些不同类型噪声的机制对于了解可以对当前设计进行哪些调整以减少这些系统发出的总体声音至关重要。潜在的降噪设计包括：具有锯齿状或多孔和柔性后缘或流苏前缘的叶片。对这些设计的有效性的研究通常是实验性的或数值性的，它们不能更深入地研究结果，告诉你为什么这样的设计是有效的，仅仅是它是否有效。这个项目的最终目的是提供为什么的答案。使用分析方法导出的数学解可以非常强大，因为它们保留了这些流体-结构相互作用问题的重要物理特性，但显著降低了计算成本，并且可以解决数值模型难以解决的情况，例如产生高频噪声。数学预测的速度可以识别需要进一步研究的重要领域，为开发新的降噪或提高性能的技术提供领先优势。通过数学分析，本项目将深入了解这些经过调整的前沿和后沿设计降低噪声的机制，并获得关键设计特征之间的关系，例如后缘适应性或原始叶片几何形状的孔隙度，以及总的噪音降低，从而允许快速优化设计，而不需要大量的实验或昂贵的计算。

项目成果

Spanwise varying porosity for the enhancement of leading-edge noise reduction

翼展方向变化的孔隙率可增强前沿降噪效果

• DOI: 10.2514/6.2021-2191
• 发表时间: 2021
• 作者: Ayton L

Trailing-edge serrations: improving theoretical noise reduction models

后缘锯齿：改进理论降噪模型

• DOI: 10.2514/6.2021-2111
• 发表时间: 2021
• 作者: Ayton L

Analytic solutions for reduced leading-edge noise aerofoils

降低翼型前沿噪声的分析解决方案

• DOI: 10.2514/6.2018-3284
• 发表时间: 2018
• 作者: Ayton L

Analytic solution for aerodynamic noise generated by plates with spanwise-varying trailing edges

• DOI: 10.1017/jfm.2018.431
• 发表时间: 2018-06
• 期刊: Journal of Fluid Mechanics
• 影响因子: 3.7
• 作者: Lorna J. Ayton

The Unified Transform: A Spectral Collocation Method for Acoustic Scattering

统一变换：声散射的光谱搭配方法

• DOI: 10.2514/6.2019-2528
• 发表时间: 2019
• 作者: Ayton L