Vortex Formation in Finite-length Shallow Flows

[09:65 . 293]罗克韦尔在世界各地的河流沿岸和潮汐区都有大量的半封闭的、类似洞穴的结构，它们的形式是直堤（石坝）、海湾和防波堤。生物生物量和大量营养物质、溶解气体、植被、鱼类和海洋生物的生存和维持适当的平衡，以及各种各样的污染物和污染物的无意或有计划的入侵，是主要关注的问题。水被吸进或从这些空腔状区域排出的有效性对水质有重要影响。这种质量交换涉及浅层混合层，其不稳定尺度和涡比水深大得多。这个程序旨在从根本上改变方法，以及我们对有限流向范围的浅混合层的理解。时空定量成像将产生有限长度浅混合层的流动结构的新表示，从而提供对空腔与其外部区域之间的质量吞没/交换的见解。这样的成像将解释由有限长度尺度和腔内驻重力波的影响引起的浅混合层内不稳定和漩涡形成的稳定和不稳定。这一方法将为空腔与其周围环境之间的质量交换提供一个新的、基于物理的框架，而不是根据经验从冲洗或净化时间确定交换系数，并最终有助于提高水的可及性和质量，这是几乎所有发达国家和不发达国家日益关注的问题。考虑到社区大学日益重要的作用，针对少数族裔学生比例较高的一所中学和一所社区大学，一项针对弱势学生的拓展计划将包括一个综合计划，有几个不同的举措。

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.