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CAREER: Flow distortions of quiet serrated structures

职业：安静锯齿状结构的流动扭曲

基本信息

批准号：
1846852
负责人：
Justin Jaworski
金额：
$ 51.08万
依托单位：
Lehigh University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-09-01 至 2023-11-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1846852&HistoricalAwards=false
关键词：
CAREER Flow distortions quiet serrated

项目摘要

Acoustic noise is an unavoidable byproduct of flows near aerodynamic structures, where noise is amplified by turbulence interactions with solid bodies. Flow-borne sound contributes to environmental noise levels that are targets for national and international aircraft noise regulations. However, noise also constrains the commercial footprints of wind turbines, emergent commercial unmanned air vehicles, and new paradigms for efficient urban air travel. To address this challenge, serrated edge designs have been adopted in engineering practice, which can affect both the noise level and the fluid dynamics. An acoustic understanding of serrations based on their flow physics remains underdeveloped, where the prevailing noise theory cannot reliably predict changes in noise level. The principal aim of this project is to develop new theoretical models for how edge serrations affect their local fluid flow and their acoustic signature.The objectives of the proposed theoretical research program are to: (1) understand via data reduction of noise experiments how serrations distort incoming flow turbulence; (2) model and predict the distortion of flows pertinent to leading edges and trailing edges; and (3) compute the effect of distorted serrations on local unsteady pressures and the radiated noise. The integrated research and education plan aims to furnish a predictive theoretical framework for serration noise generation, which will be coordinated with global research partners for experimental and numerical validation and will provide international research exchange opportunities for graduate students. 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).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.

声学噪声是空气动力结构附近流动不可避免的副产品，其中噪声因湍流与固体的相互作用而被放大。流动声音会导致环境噪声水平达到国家和国际飞机噪声法规的目标。然而，噪音也限制了风力涡轮机、新兴商用无人机以及高效城市空中旅行的新范例的商业足迹。为了应对这一挑战，工程实践中采用了锯齿状边缘设计，这会影响噪声水平和流体动力学。基于锯齿流动物理学的声学理解仍然不发达，流行的噪声理论无法可靠地预测噪声水平的变化。该项目的主要目的是开发新的理论模型，研究边缘锯齿如何影响其局部流体流动及其声学特征。所提出的理论研究计划的目标是：（1）通过噪声实验的数据减少来了解锯齿如何扭曲传入的流动湍流； (2) 建模并预测与前缘和后缘相关的流动畸变； (3) 计算扭曲锯齿对局部不稳定压力和辐射噪声的影响。该综合研究和教育计划旨在为锯齿噪声的产生提供一个预测理论框架，该框架将与全球研究合作伙伴协调进行实验和数值验证，并为研究生提供国际研究交流机会。该项目还将包括与达芬奇科学中心（宾夕法尼亚州阿伦敦）的 K-12 教育推广，以及通过 Lehigh Biosystems Dynamics 暑期学院（与北安普顿社区学院合作）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价值和更广泛的影响审查标准进行评估，被认为值得支持。