UNS: Physical Mechanisms of Wall-Bounded Turbulence and Turbulent Mixing at Extreme Reynolds

1510100(Hultmark)拟议研究的目标是提高我们对接近固体物体的湍流的理论理解和建模，固体物体是工程应用中最重要和最相关的湍流类别(因为工业过程、航空航天和海军应用中的湍流以及大气边界层中的湍流属于这一类别)。由于湍流的复杂性，获取高质量的实验数据以及在具有实际意义和验证理论进展所需的尺度和分辨率下进行高保真的数值模拟是非常具有挑战性的。详细的研究常常被简单的参数化和相关性所取代。动量传递和热传递之间的简单类比一直是大多数湍流传热模型的基础，尽管众所周知，这些类比在许多应用中表现不佳。虽然在过去的二十年中取得了重大的突破，但目前的仪器仍然存在局限性，高雷诺数的研究往往仅限于速度矢量的一个分量的测量。这就是拟议工作的贡献所在：它提出了一种研究大范围雷诺数范围内的湍流输运的方法。提出了采用新型MEMS流量传感器来克服实验局限性的方法。通过将所提出的新型仪器与加热管流装置相结合，普林斯顿超级管道有望以极高的雷诺数获得前所未有的多组分速度和温度数据。此外，还将开展基础理论工作，将湍流换热研究与湍流动量研究结合起来。这项工作的结果如果成功，将有可能提高世界各地实验室的能力。建议开展包括研究生和本科生在内的教育和外联活动，以及调整本科实验室课程。该项目的活动将从普林斯顿现有的REU项目中获得杠杆作用。

1510100(Hultmark)The goal of the proposed research is to improve our theoretical understanding and modeling of turbulent flow close to a solid object, which is the most important and relevant to engineering applications class of turbulent flows (since turbulence found in industrial processes, aerospace and naval applications, and in the atmospheric boundary layer fall within this class). A new experimental technique for measuring velocity fluctuations at resolutions that are one order of magnitude finer than currently available techniques is also proposed.Because of the complexity of turbulent flows, it is very challenging to obtain high quality experimental data and to conduct high fidelity numerical simulations at the scales and resolutions that have practical interest and that are needed to validate theoretical advances. Detailed studies have often been replaced with simple parameterizations and correlations. Simple analogies between momentum transfer and heat transfer have been the foundation for most turbulent heat transfer models, even if it is well-known that these analogies perform poorly in many applications. While significant breakthroughs have taken place in the last twenty years, there are still limitations in current instrumentation and high Reynolds number studies have often been limited to measurements of only one component of the velocity vector. This is where the contribution of the proposed work is: it proposes a study of turbulent transport over a wide range of Reynolds numbers. It is proposed to overcome experimental limitations by deploying novel MEMS-based flow sensors. By combining the proposed novel instrumentation with a heated pipe-flow facility, unprecedented multi-component velocity and temperature data are expected to be obtained in a unique facility, the Princeton Superpipe, at extreme Reynolds numbers. In addition fundamental theoretical work will be conducted to integrate the study of turbulent heat transfer with turbulent momentum studies. Results from this work, if successful, has the potential to increase the capabilities of laboratory setups across the world. Educational and outreach activities that include graduate and undergraduate students, and restructuring of undergraduate lab courses are proposed. Activities of the project will find leverage from an existing REU program at Princeton.