Evolution and Viscous Decay of Dipolar Vortex Couples in Two Dimensional Fluid Mechanics

二维流体力学中偶极涡对的演化和粘性衰变

• 批准号: 9206828
• 负责人: Seth Lichter
• 金额: $ 26.69万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-08-15 至 1996-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9206828&HistoricalAwards=false
• 关键词: Evolution; Viscous; Decay; Dipolar; Vortex

A joint analytical and experimental investigation is to be conducted of the viscous decay, evolution and interaction of vortex couples at large Reynolds number. Analytically, boundary layer ideas are used to derive their behavior from known inviscid solutions. The interaction of vortex couples with weak background vorticity or shear is studied using singular perturbation theory. By studying mixing in the large Peclet number limit, estimates on the efficiency of vortex couples in transport are derived. The experiments employ a novel use of stratification to create two-dimensional flows. Mixing is studied quantitatively by the optical tracking of tracer particles and dye. Data processing determines the velocity and vorticity fields as they evolve. Vortex couples, localised dipolar regions of vorticity, possess nearly closed streamlines, are self-propagating, and persist for long times. Consequently, they efficiently transport vorticity, momentum, heat and contaminants. Vortex couples arise in the shear layers and plumes observed in atmospheric chemistry, ocean mixing, convective cooling, and turbulent transport and mixing.

一项联合分析和实验研究将在 进行了粘性衰减，演变和相互作用， 大雷诺数时涡偶。 分析上， 边界层的想法是用来推导他们的行为， 已知的非粘性溶液。 涡偶的相互作用 弱背景涡度或切变的情况下， 奇异摄动理论 通过研究大范围的混合 Peclet数极限，涡效率的估算 在运输中的夫妇派生。 实验采用了 新的使用分层来创建二维流。 混合是定量研究的光学跟踪 示踪粒子和染料。 数据处理决定了 速度场和涡度场 涡偶，局部偶极涡区， 具有接近封闭的流线，是自传播的， 坚持很长时间。 因此，他们有效地 输送涡量、动量、热量和污染物。 涡流 电偶出现在剪切层中， 大气化学，海洋混合，对流冷却， 湍流输送和混合。