Vortex Formation in Finite-length Shallow Flows

有限长度浅流中涡的形成

• 批准号: 0965293
• 负责人: Donald Rockwell
• 金额: $ 25万
• 依托单位: Lehigh University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-15 至 2014-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0965293&HistoricalAwards=false
• 关键词: Vortex; Formation; Finite; length; Shallow

0965293RockwellA large number of semi enclosed, cavity like configurations in the form of spur dikes (groynes), embayments, and jetties are located along rivers and in tidal regions around the world. The survival and maintenance of proper balances of living biomass and masses of nutrients, dissolved gases, vegetation, fish, and marine life, as well as the inadvertent or planned intrusion of a wide variety of pollutants and contaminants, are major concerns. The effectiveness with which water is drawn into, or purged from, these cavity like regions has important consequences for water quality. Such mass exchange involves shallow mixing layers, which have scales of instabilities and vortices much larger than the water depth. This program aims to fundamentally alter the approaches to, and our understanding of, shallow mixing layers of finite streamwise extent. Space time quantitative imaging will yield new representations of the flow structure of finite length shallow mixing layers, and thereby provide insight into the mass engulfment/exchange between the cavity and the region exterior to it. Such imaging will account for stabilization and destabilization of instabilities and vortex formation within the shallow mixing layer, arising from the effects of finite length scale and a standing gravity wave within the cavity. This approach will lead to a new, physics based framework for mass exchange between the cavity and its surroundings, in contrast to exchange coefficients empirically determined from flushing or purging times, and eventually contribute to enhanced water accessibility and quality, which is of increasing concern to nearly all developed and underdeveloped countries. An outreach program for underrepresented students will involve an integrated program, with several different initiatives, for a middle school and a community college having high percentages of minorities, in anticipation of the increasingly important role of community colleges.

在世界各地的沿着和潮汐地区，有大量的半封闭、空腔状的丁坝（丁坝）、海湾和突堤。生物量和大量营养物、溶解气体、植被、鱼类和海洋生物的生存和维持适当平衡，以及各种污染物和污染物的无意或有计划的侵入，都是主要关切问题。 水被吸入这些空腔状区域或从这些空腔状区域排出的有效性对水质具有重要影响。这种质量交换涉及浅混合层，其不稳定性和涡的尺度比水深大得多。 该计划的目的是从根本上改变的方法，和我们的理解，有限的流向范围的浅混合层。时空定量成像将产生有限长度浅层混合层流动结构的新表示，从而提供对空腔与其外部区域之间质量吞没/交换的洞察。这种成像将解释不稳定性和涡旋的稳定性和不稳定性浅层混合层内的形成，由有限长度尺度和空腔内的重力驻波的影响引起。这种方法将导致一个新的，基于物理学的框架之间的空腔和周围环境的质量交换，交换系数经验确定的冲洗或清洗时间，并最终有助于提高水的可及性和质量，这是越来越多的关注几乎所有发达国家和欠发达国家。 针对代表性不足的学生的外联方案将涉及一个综合方案，其中有几个不同的举措，针对少数民族比例较高的中学和社区学院，以应对社区学院日益重要的作用。