Global conservation of momentum applied to environmental flows

应用于环境流的全球动量守恒

• 批准号: EP/G055602/1
• 负责人: Ian Eames
• 金额: $ 0.75万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FG055602%2F1
• 关键词: Global; conservation; momentum; applied; environmental

The application of global momentum conservation principles to multiphase flows is a relatively new approach to understand what happens when discrete elements move and disappear (see references in Part 1). This is important, for instance, when vapour bubbles rise and condense, or fuel droplets move and evaporate. After the elements have disappeared (in the sense that there is no boundary on which the kinematic condition is applied), a vortex is left behind. The momentum approach enables the final state of the flow signature and properties of the vortex to related to the initial properties of the droplets or the history of forces acting on the bubbles. These ideas and concepts have been tested experimentally and theoretically, and the framework is complete for the case of linear momentum.The aim of this current proposal is to extend this research to problems in environmental fluids mechanics. Specifically there are two areas of interest here : free surface flows and self-propelled bodies. Quantifying the momentum of wave is known to be fraught with problems; for wave trains it is more usual to discuss momentum flux [1]. One area where applying momentum conservation might be useful is the problem of compact local wave groups or tsunamis. The second area of interest is in self-propelled bodies, such as submarines. The critical issue is the flow signature they generate when they move unsteadily and whether these signatures can be detected. Both these problems are important in their own right and some aspects may be understood by applying global conservation of momentum. The key problem is setting down the conceptual framework in a rigorous manner and to test these ideas experimentally.The importance of visiting Arizona State University is underlined by two research areas in which it leads internationally: (a) Depressed tsunami dynamics. Tsunami research is currently quite active owing to the devistating effect of the Indian Ocean tsunami December 25th 2006. Prof Fernando (ASU) led the NSF scientific fact-finding group to Sri-Lanka and the results have been disseminated quite widely. One of the key aspects of their recent experimental work on depressed tsunamis was the ability to remove the tail of the depressed tsunami using, what they refer to as a leaky paddle . The experimental work was undertaken a DTA student from UCL who stayed at ASU for 3 months. (b) Subsurface signatures generated by moving submarines. Voropayev and his colleagues have been particularly active in this area having published half a dozen papers on the topic in the last few years. Voropayev is a leader in the vortex dynamics in stratified and homogeneous fluids and he has developed a very general understanding of the develop of vortex signatures interacting with the free surface, caused by the unsteady rectilinear motion of a submarine (modelled as a jet). Using similarity theory and scaling analysis enabled Voropayev to make some clear statements about the revealing surface signatures.

全局动量保护原理在多相流中的应用是一种相对较新的方法，可以理解当离散元素移动和消失时会发生什么（请参阅第1部分中的参考文献）。例如，当蒸气气泡上升和凝结或燃料液滴移动并蒸发时，这很重要。在元素消失后（从某种意义上说，没有施加运动学条件的边界），就留下了涡流。动量方法可以使涡流和涡流的最终状态与液滴的初始特性或作用在气泡上的力史有关。这些思想和概念已经在实验和理论上进行了测试，对于线性动量的情况，该框架已完成。该当前建议的目的是将这项研究扩展到环境流体机制的问题。具体而言，这里有两个感兴趣的领域：自由表面流和自旋转的身体。已知量化波动的动量充满了问题。对于波列，讨论动量通量[1]更常见。紧凑的局部波团或海啸的问题是，应用动量保护可能是有用的一个区域。感兴趣的第二个领域是自塑体，例如潜艇。关键问题是当它们不稳定地移动时产生的流签名以及是否可以检测到这些签名。这两个问题本身都很重要，并且通过应用全球势头保护可以理解某些方面。关键问题是以严格的方式设置概念框架并通过实验测试这些想法。访问亚利桑那州立大学的重要性是由它在国际上领导的两个研究领域强调的：（a）沮丧的海啸动态。由于印度洋海啸的偏差效应，2006年12月25日，海啸研究目前非常活跃。费尔南多教授（ASU）将NSF科学事实发现组带到了斯里兰卡，因此结果已被广泛传播。他们最近在抑郁海啸上的实验性工作的关键方面之一是能够使用它们称为漏水的桨，去除抑郁症海啸的尾巴。实验性工作是从UCL的DTA学生进行的，他在ASU呆了3个月。 （b）通过移动潜艇生成的地下签名。 Voropayev及其同事在这一领域特别活跃，在过去的几年中发表了有关该主题的六篇论文。 Voropayev是分层和均质流体中涡流动力学的领导者，他对与自由表面相互作用的涡流特征的发展有了非常普遍的了解，这是由潜水艇的不稳定直线运动引起的（建模为JET）。使用相似性理论和缩放分析使Voropayev能够对揭示表面特征做出一些清晰的陈述。