The small-scale structure of the fluctuating passive scalar field in a turbulent boundary layer

湍流边界层脉动被动标量场的小尺度结构

• 批准号: 0303406
• 负责人: Donald Webster
• 金额: $ 9.89万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-15 至 2006-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0303406&HistoricalAwards=false
• 关键词: small; scale; structure; fluctuating; passive

ABSTRACTPROPOSAL NO.: CTS-0303406PROPOSAL TYPE: INVESTIGATOR INITIATEDPRINCIPAL INVESTIGATORS: DONALD R. WEBSTERINSTITUTION: GEORGIA TECH. THE SMALL-SCALE STRUCTURE OF FLUCTUATING PASSIVE SCALAR FIELD IN A TURBULENT BOUNDARY LAYERMixing and transport of passive scalars in turbulent flows are important processes occurring in many natural and engineered environments. Common examples include contaminant discharges in water bodies, chemical plumes in the atmosphere, and chemical mixing in reactors. Despite decades of research aimed at understanding the dynamics of turbulent transport, scalar fields continue to defy accurate theoretical predictions. The lack of a general theory to predict the statistical nature of turbulent transport ultimately requires experimental tests to predict and optimize mixing efficiency for many practical situations. This procedure is inefficient and costly, thus a universal theory for turbulent fluctuations of scalar quantities continues to be highly desirable. This study of a turbulent shear flow has the following objectives: (1) examine the dynamics of the scalar variance dissipation rate, and (2) study the behavior and usefulness of multi-point correlators as a tool to represent small-scale turbulence structure and its relation to the traditional structure functions. We additionally propose to examine the isotropic and anisotropic components of structure functions and their respective scaling behavior. Experiments will be performed for a chemical plume in a turbulent boundary layer of an open channel flow. The planar laser induced fluorescence (PLIF) technique will be used to record time series of the high Schmidt number concentration fields. The measurements resolve the Batchelor length scale of the scalar field. Variation among three Reynolds numbers and three mean scalar gradient cases will be examined. The proposed experimental results will impact both modeling strategies and our fundamental understanding of the coupling between small-scale and large-scale behavior in turbulent shear flows. One graduate student (Ph.D. level) and one undergraduate student will be trained in advanced experimental techniques and fundamental turbulence research. Georgia Tech is a national leader in graduate education of underrepresented groups, and every effort will be made to attract such a student to this project..

Abstract Propoposs no。：CTS-0303406 PROPOPOSAS类型：研究人员发起的Principal调查人员：Donald R. WebSterinstitution：Georgia Tech。在湍流流动中的湍流边界和被动标量在湍流中的传输中波动的被动标量场的小尺度结构是在许多自然和工程环境中发生的重要过程。 常见的例子包括水体中的污染物排放，大气中的化学羽和反应堆中的化学混合。 尽管数十年的研究旨在了解湍流运输的动态，但标量场仍继续违背准确的理论预测。 缺乏预测湍流转运的统计性质的一般理论最终需要实验测试，以预测和优化许多实际情况的混合效率。 该过程效率低下且昂贵，因此，标量数量的湍流波动的通用理论仍然是非常可取的。 这项对湍流剪切流的研究具有以下目标：（1）检查标量方差耗散率的动力学，（2）研究多点相关器作为表示小规模湍流结构及其与传统结构功能的关系的工具。 我们还建议检查结构函数的各向同性和各向异性成分及其各自的缩放行为。 将在开放通道流的湍流边界层中对化学羽流进行实验。 平面激光诱导的荧光（PLIF）技术将用于记录高施密特数浓度场的时间序列。 测量值解决标量场的批次长度尺度。 将检查三个雷诺数和三个平均标量梯度病例的变化。 提出的实验结果将影响建模策略以及我们对湍流剪切流中小规模和大规模行为之间耦合的基本理解。 一名研究生（博士学位）和一名本科生将接受高级实验技术和基本湍流研究的培训。 佐治亚理工学院是代表性不足的团体研究生教育的全国领导者，将尽一切努力吸引这样的学生进入该项目。