Fundamentals of Wall-Bounded Turbulence at Extreme Reynolds Numbers

1064257 Smits高雷诺数壁面湍流的理解是非常重要的基础和实际意义，因为它是在广泛的流动，包括飞机和船舶的流动，管道和导管中的流动，以及地球大气中的流动。 然而，大多数实验室和计算研究都局限于相对较低的雷诺数，因此湍流中最基本的问题之一是如何将在低雷诺数下获得的知识扩展到高雷诺数。 此外，我们现在知道，不同的流动可以表现出不同的行为：管道，通道和边界层可以显示出显着不同的行为，那么我们如何协调这些不同的观察结果？在这里，我们提出了一个全面的研究湍流在非常高的雷诺数在管流和边界层，以帮助回答这些问题。 我们独特的定位进行这项工作，因为我们有流动设施，可以产生非常高的雷诺数湍流在管道和边界层，我们还开发了（在以前的NSF支持下）一个新的探头能够测量湍流的空间和时间分辨率约两个数量级小于传统的热线仪器。这些工具使我们能够研究雷诺数是至少一个数量级高于以前的实验室研究能够实现的条件下的完整的空间和时间resolution.The智力价值的拟议工作依赖于我们试图回答的基本问题。具体来说，我们将使用我们的测量来回答最近发现的关于高雷诺数下湍流行为的具体争议。 例如，湍流边界层的观测表明，远离壁面的大尺度湍流对壁面附近的湍流有很强的影响。 在湍流管流中的观测没有显示出这种相关性。 了解这种差异是开发近壁模型的关键一步，近壁模型对于准确预测工业和其他实际应用中的湍流至关重要。 因此，更广泛的影响的工作主要是提高我们的能力，预测和管理高雷诺数湍流。 通过这种方式，我们希望支持更安全、更高效的飞机和船舶的设计，并提供更好的模型来提高全球循环模型等的质量和准确性，同时帮助设计更好的石油和天然气管道系统。 此外，我们将建立一个积极的计划，利用这项研究工作，以帮助教育学生在科学和工程，从K-12到博士后水平，并分发新的知识，尽可能广泛地通过期刊出版物，会议演示文稿和教育材料的基础上，我们的研究经验。

1064257SmitsThe understanding of high Reynolds number wall-bounded turbulence is of great fundamental and practical importance, since it is observed in a wide range of flows, including flows over aircraft and ships, flow in pipelines and ducts, and the flow in the Earth's atmosphere. However, most laboratory and computational studies are restricted to relatively low Reynolds numbers, and so one of the most fundamental questions in turbulence is how knowledge gained at low Reynolds number can be extended to high Reynolds numbers. In addition, we now know that different flows can behave differently: pipes, channels, and boundary layers can display significantly different behavior, and so how do we reconcile these different observations?Here, we propose a comprehensive study of turbulence at very high Reynolds numbers in pipe flows and boundary layers, to help answer these questions. We are uniquely positioned to conduct this work because we have flow facilities that can produce very high Reynolds number turbulent flows in pipes and boundary layers, and we have also developed (under previous NSF support) a new probe capable of measuring turbulence with a spatial and temporal resolution about two orders of magnitude smaller than conventional hot wire instrumentation. These tools allows us to study Reynolds numbers are at least an order of magnitude higher than previous laboratory studies were able to achieve under conditions of full spatial and temporal resolution.The intellectual merit of the proposed work rests on the fundamental questions we seek to answer. Specifically, we will use our measurements to answer specific controversies recently discovered regarding the behavior of turbulence at high Reynolds number. For example, observations in turbulent boundary layers show a strong influence of the large-scale turbulence away from the wall on the turbulence near the wall. Observations in turbulent pipe flow do not show this correlation. Understanding the difference is a crucial step in developing near-wall models that are essential for accurate predictions of turbulent flow in industry and other practical applications. Hence the broader impact of the work is primarily to improve our ability to predict and manage high Reynolds turbulent number flows. In this way, we hope to support the design of safer and more efficient aircraft and ships, and provide better models to improve the quality and accuracy of, for example, Global Circulation Models, in addition to helping to design better oil and gas pipeline systems. Furthermore, we will build an aggressive program to use this research work to help educate students in science and engineering, from K-12 to postdoctoral levels, and to distribute the new knowledge as widely as possible through journal publications, conference presentations, and educational materials based on our research experience.