Establishing universal scaling laws for pressure fluctuations in high Reynolds number rough wall turbulent boundary layers

PI：Devenport，William JProposal number：1436088本研究的目的是从实验和理论上研究粗糙壁面上高雷诺数边界层中压力脉动的标度。这项工作的重点将是与实际和科学相关的条件，大多数车辆在这些条件下运行，在这些条件下最有可能观察到普遍的行为。这项研究的结果可能会对工程上预测边界层产生的声音和振动产生强烈的影响，并随着粗糙壁边界层压力谱预测函数的发展而对压力效应的科学理解产生强烈的影响。建议的工作基于最近的发现，粗糙表面上湍流边界层内的压力波动与速度波动的行为不同，这种不同的行为是重要的。PI建议在弗吉尼亚理工大学一个相当独特的设施中进行实验，以探索壁压谱和它揭示的湍流尺度。先前的结果表明，存在三个不同的标度区域(低、中和高频)，所提出的实验旨在确定这些标度的持久性，以及它们所暗示的物理过程，因为粗糙元素的几何和密度是不同的。还提出了在双尺度表面上的实验，该实验可能导致开发粗糙壁边界层压力谱的内插函数。这项拟议的工作将对边界层湍流理论在工程应用中具有重要意义，其中噪声是一个令人担忧的问题，例如车辆设计(汽车、飞机、直升机)和风力涡轮机。该提案还提出了一项将研究与教育相结合的计划。高中生、本科生和研究生将参与设计和建造部分风洞，以及制造新的粗糙表面，提供完整的动手工程体验。

PI: Devenport, William JProposal Number: 1436088The goal of the proposed research is to investigate experimentally and theoretically the scaling of pressure fluctuations in high Reynolds number boundary layers over rough walls. The focus of the work will be on practically and scientifically-relevant conditions at which most vehicles operate and at which universal behaviors are most likely to be observed. Results from the proposed research could have a strong impact on engineering for prediction of sound and vibration produced by boundary layers, and on scientific understanding of pressure effects with the development of a predictive function for rough-wall boundary layer pressure spectra.The proposed work is based on recent findings that pressure fluctuations within turbulent boundary layers over rough surfaces behave differently that velocity fluctuations, and this different behavior is important. The PI proposes to conduct experiments in a rather unique facility at Virginia Tech to explore the wall-pressure spectrum and the turbulence scales that it reveals. Prior results indicate that there are three different scaling regions (low, medium and high frequency), and the proposed experiments aim to establish the persistence of these scalings, and the physical processes they imply, as the geometry and density of the roughness elements is varied. Proposed are also experiments on a two-scale surface that could lead to the development of an interpolation function for rough-wall boundary layer pressure spectra. The proposed work would be important for the theory of boundary layer turbulence with engineering applications where noise is a concern, such as vehicle design (cars, planes, helicopters) and wind turbines. The proposal also offers a plan to integrate research with education. High school, undergraduate and graduate students will be involved in designing and building parts of the wind tunnel as well as manufacturing of the new rough surfaces, providing a complete hands-on, engineering experience.