Collaborative Research: The Pressure Shielding of Aerodynamic Surfaces

诸如风涡轮机叶片、飞机机翼、螺旋桨或风扇的装置的表面都被设计成以有益的方式管理空气流。然而，不可避免地伴随流动的湍流在表面上产生压力波动，这可能导致不期望的振动或声音。这项研究工作旨在了解如何将处理放置在表面上方，从而能够大幅降低压力波动，而不会对表面对流动的有益影响产生负面影响。这项工作将包括在弗吉尼亚理工大学进行的协调风洞实验和在佛罗里达大西洋大学进行的理论研究。除了推进流体动力学领域的科学和工程外，这项工作还将集中在博士和本科生的研究培训上。特别是，这些实验将与弗吉尼亚理工大学所需的本科生实验室相结合，在整个项目过程中影响了数百名学生。这项工作的主要目标是为表面处理建立基本的科学基础，以减少湍流表面压力波动，同时保持大多数流体动力学应用所需的动量和低阻力的壁面正常传输。最近的研究已经明确表明，压力屏蔽是可能的。这项工作的目的是提供一个定量的可用的基本了解这些影响背后的机制，以及所需的数学方法进行预测。 该研究计划的重点是应用压力屏蔽处理两个基本流;无剪切边界层形成的壁附近的均匀湍流，和一个传统的平板湍流边界层。选择这些流动是因为它们干净地分离了预期负责压力屏蔽的一些主要机制。它们在几何上也是简单的，并且很好地表征，因为存在这些流的完整相关结构的分析或实验模型。在弗吉尼亚理工大学将对这些配置进行大规模的实验，无论是否进行处理。并行数学建模将在佛罗里达大西洋大学进行。通过这项密切相关的研究，我们不仅希望提取压力屏蔽的基本性质，而且还希望建立预测所需的数学基础良好的分析工具。一个关键的目标是提供研究教育，以学生从广泛的学术水平绘制的多样化群体。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The surfaces of devices such as a wind turbine blade, of an airplane wing, of a propeller or fan are all designed to manage the flow of air in a beneficial way. However, turbulence that inevitably accompanies the flow produces pressure fluctuations on a surface that can result in undesirable vibration or sound. This research effort is directed at understanding how treatments placed just above a surface might be able to substantially reduce the pressure fluctuations, without negatively impacting the beneficial effects of a surface on the flow. The work will involve coordinated wind tunnel experiments at Virginia Tech, and theoretical studies at Florida Atlantic University. As well as advancing science and engineering in the area of fluid dynamics, the effort will be focused on the research training of PhD and undergraduate students. In particular the experiments will be integrated with required undergraduate laboratories at Virginia Tech, impacting several hundred students over the course of the project.The main objective of this work is to establish the fundamental scientific basis for surface treatments that reduce turbulent surface pressure fluctuations, while maintaining the wall-normal transport of momentum and low drag that is required in most fluid dynamic applications. Recent studies have definitively demonstrated that pressure shielding is possible. The purpose of this work is to provide a quantitatively usable fundamental understanding of the mechanisms behind these effects, and the mathematical methods needed for their prediction. The research program is focused on the application of pressure shielding treatments to two fundamental flows; the shear-free boundary layer formed adjacent to a wall in homogeneous turbulence, and a conventional flat plate turbulent boundary layer. These flows have been chosen since they cleanly separate some of the major mechanisms expected to be responsible for pressure shielding. They are also geometrically simple and well characterized, since analytical or experimental models of the complete correlation structure of these flows exist. Large scale experiments on these configurations with and without treatment, will be performed at Virginia Tech. Parallel mathematical modeling will be carried out at Florida Atlantic University. Through this closely linked study we expect not only to extract the fundamental nature of the pressure shielding, but also to build mathematically well-founded analytical tools needed for its prediction. A key goal is to provide research education to a diverse group of students drawn from a broad range of academic levels. The planned work includes specific tasks to be conducted by groups of undergraduate and high school students across both institutions.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.