Collaborative Research: Measurements and Modeling of Subgrid-scale Turbulence in the Atmospheric Surface Layer

合作研究：大气表层亚网格尺度湍流的测量和建模

• 批准号: 0638392
• 负责人: Chenning Tong
• 金额: $ 38.95万
• 依托单位: Clemson University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0638392&HistoricalAwards=false
• 关键词: Collaborative; Research; Measurements; Modeling; Subgrid

This research will be conducted collaboratively at Clemson University, the Pennsylvania State University, and the National Center for Atmospheric Research. It focuses on issues met in using large-eddy simulation (LES) to predict the statistics of the atmospheric boundary layer (ABL). LES has become an effective research tool for the ABL and probably the most important simulation method for it. In LES, processes occurring on scales too small to be resolved by the numerical grid are diagnosed based on larger scale processes that can be resolved by the grid, using a subgrid-scale (SGS) model. However, near the ground, in the atmospheric surface layer, LES suffers from inherent under-resolution and poor SGS model performance. An integrated research program will be conducted consisting of field measurements and numerical simulations to improve SGS model performance. This research investigates the impact of the SGS turbulence on the resolvable-scale statistics in the surface layer by using field measurements to analyze the transport equations of SGS stress and flux, and the transport equation of the joint probability density function (JPDF) of resolvable-scale velocity and scalars. The field program will employ the array technique developed during prior NSF-supported research to measure the resolvable- and subgrid-scale variables. It will, for the first time, include measurements of the advection of the SGS stress and flux, which is essential for studying the SGS dynamics and for evaluating the new SGS models. The observations will be further analyzed by obtaining modeled SGS stress and flux using LES fields as model inputs to compute the SGS variables in the JPDF equation, which then will be compared with observations. This research is expected to significantly advance the understanding of the dynamics of the SGS stress and temperature flux, and their impact on the resolvable-scale dynamics. The research has broader impacts in several areas. It will provide education and research opportunities for two graduate students. New data analyses and processing methods developed in this research will further the understanding of the potentials and limitations of the array measurement technique as an essential tool for other important boundary layer applications such as area-averaged flux measurements. Improved LES will be important for improving predictive tools for applications to air-pollution modeling, weather forecasting, and land-atmosphere interaction modeling. These improved tools will greatly benefit society.

这项研究将在克莱姆森大学、宾夕法尼亚州立大学和国家大气研究中心合作进行。 它集中在使用大涡模拟（LES）预测大气边界层（ABL）的统计遇到的问题。 大涡模拟已经成为大气边界层的一种有效的研究工具，并且可能是最重要的模拟方法。在大涡模拟中，尺度太小而不能被数值网格分辨的过程，可以通过网格分辨的大尺度过程来诊断，使用亚网格尺度（SGS）模型。 然而，在近地面，在大气表层，LES遭受固有的分辨率和SGS模式性能差。将进行一项综合研究计划，包括实地测量和数值模拟，以提高SGS模型的性能。 本文利用实测资料分析了SGS应力和通量的输运方程以及可分辨尺度速度和标量的联合概率密度函数（JPDF）的输运方程，研究了SGS湍流对近地面层可分辨尺度统计的影响。 现场计划将采用在先前NSF支持的研究中开发的阵列技术来测量可分辨和亚网格尺度变量。 它将首次包括SGS应力和通量平流的测量，这对于研究SGS动力学和评估新的SGS模型至关重要。 通过使用LES场作为模型输入来获得建模的SGS应力和通量，以计算JPDF方程中的SGS变量，然后将其与观测值进行比较，从而进一步分析观测值。 这项研究预计将显着推进的SGS应力和温度通量的动力学，以及它们对可分辨尺度动力学的影响的理解。 这项研究在几个领域产生了更广泛的影响。 它将为两名研究生提供教育和研究机会。 在这项研究中开发的新的数据分析和处理方法将进一步了解阵列测量技术的潜力和局限性，作为其他重要的边界层应用，如面积平均通量测量的重要工具。 改进的LES对于改进应用于空气污染建模、天气预报和陆-气相互作用建模的预测工具将是重要的。 这些改进的工具将大大造福社会。