Analytical and Numerical Studies of Deep Overflows and Related Circulations

知识价值：该项目旨在通过对与广阔盆地相连的双层流旋转水力学的全面研究，扩展我们目前对深层溢流的理解。两层动力学被认为在许多重要通道的溢流中是重要的，包括丹麦海峡、法罗海峡和维马海峡，无论是在考虑地表逆流的影响，还是在考虑流入河道并包含在溢流中的不同水团的演变。本研究将分析和数值技术应用于许多基本问题，包括交换流和单向流情况下两层水力学理论与邻近盆地流动的动态一致联系，深层抽吸，水力控制识别的一般方法和特殊特征的隔离，如任意截面渠道中的水力跳跃，以及海峡和盆-海峡耦合系统中时间依赖性的作用。阐明这些问题将有助于解释更复杂的数值模型和观测结果，并有助于规划上游流域内溢流运输的长期监测战略。此外，研究人员将继续寻找呈现结果的方法，以便有利于直觉，并为非专业人员所接受。更广泛的影响：深层通道提供了监测倾覆循环的理想点。然而，这只能在水力学理论的发展与改进的现实性和一旦海峡和盆地流动之间的动态联系被理解之后才能正确地完成。这项工作将开始回答其中的一些问题，应该是广泛的兴趣超出了具体的动力学探讨在这里。这两位研究者都活跃在MIT/WHOI联合项目中，这项研究的结果将很快进入课堂。拨款的一小部分将用于支持完成一篇关于海洋海峡和静止流以及水力学在地球物理学中的其他应用的研究生论文。该基金还将为研究生完成论文提供持续支持。

Intellectual Merit:This project seeks to extend our current understanding of deep overflows through a comprehensive study of rotating hydraulics of two-layer sill flows connected to broad basins. Two-layer dynamics are thought to be important in the overflows of a number of important passages, including the Denmark Strait, the Faroe-Bank Channel, and the Vema Channel, either in accounting for the influence of reverse flows at the surface or the evolution of distinct water masses feeding the channel and contained within the overflows. This study brings analytical and numerical techniques to bear on a number of fundamental issues including the dynamically consistent connection of two-layer hydraulic theory to the neighboring basin flows for both exchange and unidirectional flow cases, aspiration of deep layers, general methods for the identification of hydraulic control and the isolation of special features such as hydraulic jumps in channels with arbitrary cross section, and the role of time-dependence in straits and coupled basin-strait systems. The elucidation of these issues will aid in the interpretation of results from more complicated numerical models, observations, and in the planning of strategies for long-term monitoring of overflow transport from within upstream basins. Also, the investigators will continue to find ways of presenting the results so as to favor the intuition and to be accessible to the non-specialist. Broader Impacts:Deep passages offer ideal points to monitor the overturning circulation. However, this can only be done properly after development of hydraulic theories with improved realism and once the dynamical connections between strait and basin flows are understood. This work will begin to answer some of these questions and should be of wide interest beyond the specific dynamics explored here. The two investigators are both active in the MIT/WHOI Joint Program and the results of this research will quickly reach the classroom. A small percentage of the grant will support the completion of a graduate text on ocean strait and sill flow and other applications of hydraulics in geophysics. The grant will also provide continuing support for a graduate student to complete his thesis.