Transport Processes in Inland and Coastal Waters

内陆和沿海水域的运输过程

• 批准号: RGPIN-2014-05686
• 负责人: Chu, Vincent
• 金额: $ 1.6万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=647697
• 关键词: Transport; Processes; Inland; Coastal; Waters

The transports of heat, contaminants and sediments in inland and coastal waters are unique and complex processes involving turbulence over a wide range of length scales. The horizontal length scale of turbulence is one to several orders of magnitude greater than is the depth of the flow. Buoyancy determines vertical exchanges, as interfacial friction and the radiation of internal waves suppress the horizontal shear instabilities. For motion of sufficiently large scales of horizontal length, the fictitious force of the Coriolis is also a deciding factor. The purpose of the research programme is to attain a fundamental understanding of these highly anisotropic processes, guided by field observations. Attention will be given to the intensification of fronts in climate-change scenarios. One long-term goal of the research programme is to assist government and industry to prepare for the impacts of climate change through "adaptation" - i.e., by planning to accommodate the changes that are expected to occur. * *Our research has produced highly cited publications that are fundamental to understanding the transport processes. The Scopus citations to the applicant's 2007, 2008, 2009, 2010, 2011, 2012 publications are 10, 8, 20, 32, 20 and 32, respectively. A laboratory study of horizontal turbulence in shallow open-channel flow by Chu and Babarutsi (1988; 55 Scopus citations), a field observation by Ingram and Chu (1987; 67 Scopus citations) and a hydrodynamic stability analysis on the shallow flow by Chu, Wu and Khayat (1991; 57 Scopus citations) are now classics, and have inspired much subsequent research reported in the first, second and third International Symposium on Shallow Flow (ISSF 2003, ISSF2008 and ISSF2012). The applicant has made many advances since, including his recent notable discovery of a wave radiation on horizontal turbulence. Through direct numerical simulations, Pinilla and Chu (2008) and Chu (2010) have determined the effect of the wave radiation, and correlated the effect on shear instabilities with Froude and Rossby numbers. Most significant of all is our discovery of a window of instability related to the Earth's rotation. In fully nonlinear models of the Gulf Stream and of the atmosphere, intense shear instability is observed to occur briefly in a narrow window centered on a critical Rossby number (Pinilla & Chu 2009; Chu 2014). The shear instability across the window is intense, brief in duration, and closely associated with the intensification of the fronts and the increase in the frequency of the severe storms that are likely related to climate change. **The study of horizontal turbulence would not have been possible without the parallel development of accurate and reliable numerical methods: in the past six years, this has been the focus of research supervised by the applicant, and is reported in a series of recent journal publications by Pinilla et al. (2010), Tan & Chu (2008, 2012, 2014), Chu & Altai (2012), Chu & Gao (2013), and Ghannadi & Chu (2014). Our research in the next five years will focus on refining the simulation of the steep gradients across the fronts. We will develop quasi-three-dimensional length-scale-partition model to simulate the interaction between the waves and turbulence. Laboratory and field investigations will study: (a) the role of wave radiation; (b) the development of the coastal boundary layer; and (c) the heat and mass transfer process through gravity-stratified interfaces. The experiments will be conducted in a new flow-visualization facility using a video-imaging method to study the waves and turbulence interaction. The brief and intense steepening of the fronts is to be correlated to the climate-change scenarios.

内陆和沿海沃茨中热量、污染物和沉积物的输送是一个独特而复杂的过程，涉及到大范围长度尺度上的湍流。湍流的水平长度尺度比流动的深度大一到几个数量级。浮力决定垂直交换，因为界面摩擦和内波辐射抑制水平剪切不稳定性。对于水平长度尺度足够大的运动，科里奥利的虚拟力也是一个决定因素。该研究计划的目的是通过实地观察，对这些高度各向异性的过程有一个基本的了解。将注意气候变化情景中锋面的强化。该研究计划的一个长期目标是协助政府和工业界通过“适应”--即，通过计划来适应预期发生的变化。* * 我们的研究产生了高引用的出版物，这些出版物对于理解运输过程至关重要。Scopus对申请人2007、2008、2009、2010、2011、2012年出版物的引用分别为10、8、20、32、20和32。Chu和Babarutsi关于浅水明渠水流水平紊流的实验研究（1988; 55 Scopus引文），Ingram和Chu的实地观察（1987; 67篇Scopus引文）和Chu，Wu和Khayat对浅水流的水动力稳定性分析（1991年; 57篇Scopus引文）现已成为经典，并激发了第一届、第二届和第三届国际浅水流研讨会上报告的许多后续研究（ISSF 2003、ISSF 2008和ISSF 2012）。此后，申请人取得了许多进展，包括他最近在水平湍流上的波辐射的显著发现。通过直接数值模拟，Pinilla和Chu（2008）和Chu（2010）确定了波辐射的影响，并将对剪切不稳定性的影响与Froude数和Rossby数相关联。最重要的是我们发现了一个与地球自转有关的不稳定窗口。在墨西哥湾流和大气的完全非线性模型中，观察到强烈的剪切不稳定性在以临界Rossby数为中心的狭窄窗口中短暂发生（Pinilla & Chu 2009; Chu 2014）。整个窗口的切变不稳定性是强烈的，持续时间短，并密切相关的锋的加强和可能与气候变化有关的强风暴的频率增加。** 如果没有精确可靠的数值方法的并行发展，水平湍流的研究是不可能的：在过去的六年中，这一直是申请人监督的研究的焦点，并且在Pinilla等人（2010），Tan & Chu的一系列最近的期刊出版物中报道。（2008，2012，2014），Chu & Altai（2012），Chu & Gao（2013），and Ghannadi & Chu（2014）. 我们在未来五年的研究将集中在改进对锋面陡峭梯度的模拟上。我们将发展准三维长度尺度分区模型来模拟波浪与湍流的相互作用。实验室和实地调查将研究：（a）波浪辐射的作用;（B）沿海边界层的发展;（c）通过重力分层界面的热量和质量转移过程。实验将在一个新的流动可视化设施中进行，使用视频成像方法研究波浪和湍流的相互作用。锋面的短暂而强烈的变陡与气候变化情景有关。