Use of Direct Numerical Simulation and Lagrangian Methods inTurbulent Transport

直接数值模拟和拉格朗日方法在湍流传输中的应用

• 批准号: 9209877
• 负责人: Thomas Hanratty
• 金额: $ 27.36万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-01 至 1996-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9209877&HistoricalAwards=false
• 关键词: Use; Direct; Numerical; Simulation; Lagrangian

The proposal is aimed at obtaining a unified treatment of turbulent mixing and of turbulent transfer to a wall of molecular species, and of spherical particles. Theory in this area has not advanced significantly over the past forty years. However, the recent availability of direct numerical simulations opens the possibility of making considerable progress. A main objective of this proposal is to exploit this opportunity. Results on the simultaneous three-dimensional time-dependent velocity and temperature fields will be obtained for a wide range of Prandtl numbers for turbulent flow in a channel and for turbulent Couette flow. Present theories will be evaluated. However, special emphasis will be placed on the relation of the structure of the temperature field to the structure of the velocity field and on how turbulent transport is modified by molecular transport. Lagrangian methods will be explored as a means to obtained better physical understanding. The temperature field is viewed as resulting from a distribution of wall sources. The exploitation of this approach has been opened up because of the possibility of studying, on the computer, the behavior of wall sources. The transport of spherical particles differs from transport of molecular species because of extraneous contributions to transport by gravity, turbophoresis and lift. These effects will be studied both in computer and in laboratory experiments. Particular attention will be given to obtaining much needed information about inertial free flight to the wall. We will also continue recent work in which we exploit Lagrangian methods to analyze sediment transport.

该建议的目的是获得一个统一的处理湍流混合和湍流转移到壁上的分子种类，以及球形颗粒。在过去的四十年里，这一领域的理论没有取得重大进展。然而，最近直接数值模拟的可用性开启了取得重大进展的可能性。这项建议的一个主要目标是利用这一机会。对于通道内的紊流和Couette紊流，将得到大范围普朗特数同时三维随时间变化的速度场和温度场的结果。目前的理论将被评估。然而，将特别强调温度场结构与速度场结构的关系，以及分子输运如何改变湍流输运。拉格朗日方法将作为获得更好的物理理解的一种手段加以探索。温度场被看作是壁面源分布的结果。由于可以在计算机上研究墙源的行为，这种方法的开发已经打开了大门。球形粒子的输运不同于分子种的输运，因为重力、湍流和升力对输运有外来的贡献。这些影响将在计算机和实验室实验中进行研究。将特别注意获得关于惯性自由飞向壁面的必要信息。我们还将继续最近的工作，利用拉格朗日方法来分析沉积物的运移。