Gravity and Turbidity Currents Interacting with Interfaces of Free Surfaces

重力和浊流与自由表面界面相互作用

• 批准号: 1067847
• 负责人: Eckart Meiburg
• 金额: $ 28万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2014-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1067847&HistoricalAwards=false
• 关键词: Gravity; Turbidity; Currents; Interacting; Interfaces

1067847MeiburgGravity currents form when a denser fluid propagates into a lighter one in a predominantly horizontal direction. They are frequently encountered in environmental and engineering applications. Examples are cold river outflows into a warmer lake, or a cold air front propagating into a warmer air mass. Turbidity currents represent a special class of gravity currents in which the driving force results from differential particle loading, as is the case for a sediment-laden river outflow. Turbidity currents are difficult to analyze, as they may exchange particles with surrounding fluid and/or a sediment bed by deposition or resuspension.In a geophysical context turbidity currents - essentially submarine avalanches - play a crucial role in the global sediment cycle, as the principal means of sediment transport across the continental shelves into the deep oceans. Ancient deposits of turbidite sand, deeply buried and compacted, also form an important class of hydrocarbon reservoirs, and the host rocks for a particular type of gold deposits. In an environmental engineering context, turbidity currents are responsible for much of the sedimentation in reservoirs, with consequent loss of water storage capacity.Frequently, gravity and turbidity currents interact with effective interfaces between stratified fluid layers, or with free surfaces. The resulting current/wave interactions give rise to a host of interesting and complex phenomena. For example, when turbidity currents form in shallow water as a result of submarine landslides, their interaction with the surface of the ocean (or lake) can result in the generation of tsunamis.To investigate the fundamental dynamics of the above types of flows, a detailed computational investigation of turbidity currents interacting with interfaces and free surfaces will be undertaken. The simulations and experiments will provide information about the various energy conversion mechanisms active in such flows, which in turn will allow us to develop simplified theoretical models for their analysis. The proposed research will develop such models for a wide range of particle-laden flows, from turbidity currents, river plumes, pyroclastic flows and powder snow avalanches, to tsunamis generated by submarine landslides. In this way, it will benefit such diverse areas as global sediment cycle research and environmental hazard assessment.

1067847Meiburg当较稠密的流体沿主要水平方向传播到较轻的流体时，就会形成重力流。它们在环境和工程应用中经常遇到。例如，冷河流入较温暖的湖泊，或者冷空气锋传播到较温暖的气团。浊流代表一类特殊的重力流，其驱动力来自不同的颗粒负载，就像充满沉积物的河流流出的情况一样。浊流很难分析，因为它们可能通过沉积或再悬浮与周围流体和/或沉积物床交换颗粒。在地球物理背景下，浊流（本质上是海底雪崩）在全球沉积物循环中发挥着至关重要的作用，作为主要的沉积物循环。沉积物穿过大陆架进入深海的方式。深埋和压实的古老浊积砂矿床也形成一类重要的油气藏，以及特定类型金矿床的母岩。在环境工程背景下，浊流是水库中大部分沉积的原因，从而导致蓄水能力的损失。重力和浊流经常与分层流体层之间的有效界面或自由表面相互作用。由此产生的电流/波相互作用产生了许多有趣且复杂的现象。例如，当海底滑坡在浅水中形成浊流时，它们与海洋（或湖泊）表面的相互作用可能导致海啸的产生。为了研究上述类型流的基本动力学，将进行与界面和自由表面相互作用的浊流的详细计算研究。模拟和实验将提供有关此类流动中活跃的各种能量转换机制的信息，这反过来将使我们能够开发用于分析的简化理论模型。拟议的研究将为各种充满颗粒的流开发此类模型，从浊流、河流羽流、火山碎屑流和粉雪雪崩，到海底滑坡产生的海啸。这样，它将有利于全球沉积物循环研究和环境危害评估等多个领域。