Interaction of a Boundary Layer with a Point Vortex

边界层与点涡的相互作用

• 批准号: 9729190
• 负责人: Seth Lichter
• 金额: $ 21万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-06-01 至 2002-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9729190&HistoricalAwards=false
• 关键词: Interaction; Boundary; Layer; Point; Vortex

ABSTRACT Proposal Number: CTS-9729190 Principal Investigator: Lichter This is a grant to explore simple models of the interaction of a vortex monopole with a wall-bounded shear layer at high Reynolds number, Re. While boundary layer theory treats layers which are thin compared to the distance to the vortex, the model proposed here considers the physically more realistic problem of a vortex which is in close proximity to, or within, the boundary layer. This work utilizes analytical models and efficient vorticity based numerical methods which have been developed previously. Many industrial processes rely on vortex enhanced mixing of mass, heat or momentum between boundary layers and the bulk flow. In other types of processes, vortices degrade performance and so their presence is discouraged. The active control of transition relies on detection of vortices and their characterization in terms of their disruptive yield. In spite of the numerous applications, fundamental questions remain on how vortices and boundary layers interact such as: the role of vortices in initiating disturbances, the extent that the thickening of a separating boundary layer alters the trajectory of the vortex, the accuracy and range of applicability of non-interacting boundary layer methods, the trajectories of vortices when near boundaries or within boundary layers and the role of vortices in entraining fluid into the boundary layer and in ejection of boundary layer vorticity. Because of the complexities of the issues involved there is a need, then, to simplify the governing equations while identifying and retaining the dominant mechanisms by which a vortex interacts with a boundary layer. The model considered here avoids the singularity present in boundary layer models and can describe boundary layer evolution to long times. The model is accurate at high Re and so complements methods whose accuracy is limited to low or moderate Re. Furthermore, it considers the compact disturbance produced by a vortex and so is an adjunct to methods which consider boundary layer receptivity to wave-like disturbances. 1 1

摘要 提案编号：CTS-9729190 主要研究者：Lichter 这是一个赠款，探讨简单的模型的相互作用的涡涡与壁有界剪切层在高雷诺数，Re。 虽然边界层理论处理的是与到涡流的距离相比较薄的层，但这里提出的模型考虑的是物理上更现实的问题，即靠近边界层或在边界层内的涡流。 这项工作利用分析模型和有效的涡量为基础的数值方法，已开发出以前。 许多工业过程依赖于边界层和整体流之间的质量、热量或动量的涡流增强混合。 在其他类型的过程中，涡流会降低性能，因此不鼓励它们的存在。 过渡的主动控制依赖于涡流的检测及其破坏性产量方面的表征。 尽管有许多应用，但关于涡流和边界层如何相互作用的基本问题仍然存在，例如：涡流在初始扰动中的作用，分离边界层增厚改变涡流轨迹的程度，非相互作用边界层方法的精度和适用范围，在边界附近或边界层内的涡的轨迹，以及涡在将流体带入边界层和喷射边界层涡量中的作用。 由于所涉及的问题的复杂性，有必要简化控制方程，同时确定并保留涡与边界层相互作用的主要机制。 该模型避免了边界层模型中的奇异性，能够描述边界层的长时间演化。 该模型是准确的，在高Re，因此补充的方法，其准确性仅限于低或中等Re。 此外，它考虑了由涡旋产生的紧凑扰动，因此是考虑边界层对波动扰动的感受性的方法的附属物。 1 1