Vorticities, Coherent Structures, and Surface Roughness Effect in Turbulent Thermal Convection

湍流热对流中的涡量、相干结构和表面粗糙度效应

• 批准号: 0071323
• 负责人: Penger Tong
• 金额: $ 30万
• 依托单位: Oklahoma State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-11-01 至 2004-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0071323&HistoricalAwards=false
• 关键词: Vorticities; Coherent; Structures; Surface; Roughness

This research uses laser light scattering and other modern experimental methods to study the shape and dynamics of the large-scale velocity structures, spatial and temporal correlations between the velocity and temperature fields, and the surface roughness effect on the heat transport in turbulent convection driven by a large temperature gradient across a fluid layer. The proposed experiments involve investigation of universal features of turbulence, such as intermittency, coherent structure, and anomalous scaling, and also include exploration and characterization of special behaviors of turbulent convection in a closed cell under different boundary conditions. Emphasis will be placed on the understanding of the dynamic process and the physical mechanism of the characteristic features of convective turbulence. The study of turbulent convection over a rough surface is directly related to the convection in the atmosphere and oceans, where the underlying surfaces are almost always rough. This research contains a combination of exploring new physics and instrumentation development. Students involved in the project will receive a broad training in physics and optics, which will prepare them for a range of careers in academe, industry or government. The development of a novel fiber-optic vorticity probe will provide a powerful tool, which can be used widely in the general area of fluid dynamics. %%%This work uses laser light scattering and other modern experimental techniques to study turbulent fluid motion driven by a large temperature gradient across a fluid layer. The proposed experiments involve investigation of the shape and dynamics of the large-scale velocity structures, spatial and temporal correlations between the velocity and temperature fields, and the surface roughness effect on the heat transport in turbulent thermal convection. These experiments are of fundamental interest for the physical understanding of convective turbulence, and they are also relevant to many practical applications. The study of turbulent convection over a rough surface is directly related to the convection in the atmosphere and oceans, where the underlying surfaces are almost always rough. Understanding the heat transport in turbulent convection will shed new light on technological improvements for more efficient heat transfer in various industrial applications ranging from heat exchangers to reentry vehicles in the space flight. This research contains a combination of exploring new physics and instrumentation development. Students involved in the project will receive a broad training in physics and optics, which will prepare them for a range of careers in academic or industrial science. The development of a novel fiber-optic vorticity probe will provide a powerful tool, which can be used widely in the general area of fluid dynamics.

本研究使用激光散射和其他现代实验方法来研究大尺度速度结构的形状和动力学，速度场和温度场之间的空间和时间相关性，以及表面粗糙度对流体层中大温度梯度驱动的湍流对流中热传输的影响。拟议的实验涉及调查的湍流的普遍特征，如不连续性，相干结构，和异常标度，也包括探索和表征的特殊行为的湍流对流在一个封闭的细胞在不同的边界条件。 重点将放在对流湍流特征的动力学过程和物理机制的理解。粗糙表面上的湍流对流的研究与大气和海洋中的对流直接相关，其中下垫面几乎总是粗糙的。这项研究包含了探索新物理和仪器开发的结合。 参与该项目的学生将接受物理和光学方面的广泛培训，这将为他们在工业，工业或政府领域的职业生涯做好准备。 新型光纤涡量探头的研制将为流体动力学领域的研究提供一种强有力的工具，可广泛应用。这项工作使用激光光散射和其他现代实验技术来研究湍流流体运动驱动的大温度梯度通过流体层。建议的实验涉及调查的形状和动态的大规模的速度结构，空间和时间之间的相关性的速度和温度场，以及表面粗糙度的影响，在湍流热对流的热传输。 这些实验对于对流湍流的物理理解具有根本意义，并且它们也与许多实际应用相关。 粗糙表面上的湍流对流的研究与大气和海洋中的对流直接相关，其中下垫面几乎总是粗糙的。 了解湍流对流中的热传输将为技术改进提供新的思路，以便在从热交换器到太空飞行中的再入飞行器的各种工业应用中实现更有效的热传递。 这项研究包含了探索新物理和仪器开发的结合。 参与该项目的学生将接受物理和光学方面的广泛培训，这将为他们在学术或工业科学领域的一系列职业生涯做好准备。 新型光纤涡量探针的研制为流体力学领域的研究提供了一种强有力的工具，具有广阔的应用前景。