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

主要研究者：Devenport，William J建议编号：1436088所提出的研究的目标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波动的标度。工作的重点将是大多数车辆运行的实际和科学相关的条件，以及最有可能观察到的普遍行为。从拟议的研究结果可能会有很大的影响，工程预测的声音和振动产生的边界层，并在科学上理解的压力效应与发展的预测功能粗糙壁边界层的压力spectrum.The拟议的工作是基于最近的发现，压力波动内湍流边界层粗糙表面表现不同的速度波动，这种不同的行为很重要。PI建议在弗吉尼亚理工大学的一个相当独特的设施中进行实验，以探索壁压谱和它所揭示的湍流尺度。先前的结果表明，有三个不同的缩放区域（低，中和高频率），和拟议的实验的目的是建立这些缩放的持久性，以及它们所暗示的物理过程，作为粗糙度元素的几何形状和密度是不同的。建议也是实验上的两个尺度的表面，可以导致粗糙壁边界层压力谱的插值函数的发展。 拟议的工作将是重要的边界层湍流理论与工程应用中的噪声是一个问题，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风洞部件的设计和建造以及新粗糙表面的制造，提供完整的动手工程经验。

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.