Geophysical fluid turbulence

地球物理流体湍流

• 批准号: 217040-2008
• 负责人: Bartello, Peter
• 金额: $ 1.82万
• 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: 2010
• 资助国家: 加拿大
• 起止时间: 2010-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=454073
• 关键词: Geophysical; fluid; turbulence

The requested funds are for the study of geophysical fluid turbulence employing high-resolution numerical simulations and analytical techniques. It goes without saying that our attempts to understand scientifically the big environmental questions of the day are extremely dependent on numerical models of the atmosphere - ocean - cryosphere - land surface system. Yet these are faced with the enormous complication of the true system. In order to account for all important physical effects, numerical shortcuts have to be made. Most important of these is that the simulated range of length and time scales, as determined by model resolution, is extremely reduced compared to reality. The victim of this brutal simplification is the turbulent mixing of all of the quantities of interest. In order to know anything about the future distributions of such vital things as carbon dioxide, ozone, pollution, etc, one needs to know their sources, their sinks and how the atmosphere-ocean system mixes them. The focus of this research is on the latter with the view that understanding turbulent mixing is a necessary first step to being able to account for it when it is not explicitly resolved. Specifically, the influence of aspects of the atmospheric and oceanic setting, such as rotation and stratification, will continue to be identified. For example, the nonlinear interactions between the resulting wave motion and the vortices, ubiquitous in turbulent flows, will be a primary focus. A number of detailed topics are presented below. They include a heightened focus on the anisotropy of passive tracer mixing, the effect of condensation and evaporation of water in this setting, the change of predictability caused by moisture, the challenging limit of stably-stratified turbulence when rotation is weak (at the heart of mesoscale meteorology and the most difficult limit in boundary-layer turbulence), the breakdown of higher-order balance and the role of small-scale vortex tube stretching in extreme events. The dependence of this work on numerical simulation implies that it is a rapidly-evolving field and research on numerical methods will continue to be undertaken in parallel. My group has been at the forefront of this type of research and has a proven track record of being useful in this regard.

申请的资金用于采用高分辨率数值模拟和分析技术研究地球物理流体湍流。 不用说，我们试图科学地理解当今重大的环境问题，是非常依赖于大气-海洋-冰冻圈-陆地表面系统的数值模型。然而，这些都面临着真正系统的巨大复杂性。为了解释所有重要的物理效应，必须采用数值上的捷径。其中最重要的是，由模型分辨率决定的模拟的长度和时间尺度范围与现实相比大大减少。 这种残酷的简化的受害者是所有利益数量的混乱混合。 为了了解诸如二氧化碳、臭氧、污染等重要物质的未来分布，人们需要知道它们的来源、它们的汇以及大气-海洋系统如何混合它们。本研究的重点是后者，认为理解湍流混合是必要的第一步，能够考虑到它时，它是没有明确解决。 具体而言，将继续查明大气和海洋环境各方面的影响，如旋转和分层。 例如，所产生的波动和涡流之间的非线性相互作用，在湍流中无处不在，将是一个主要的焦点。 下文介绍了一些详细的专题。 它们包括对被动示踪剂混合的各向异性的高度关注，在这种情况下水的凝结和蒸发的影响，由水分引起的可预报性的变化，当旋转较弱时稳定分层湍流的挑战性极限（中尺度气象学的核心和边界层湍流中最困难的限制），高阶平衡的破坏和小尺度涡管拉伸在极端事件中的作用。这项工作对数值模拟的依赖意味着它是一个快速发展的领域，数值方法的研究将继续并行进行。 我的团队一直处于这类研究的前沿，并在这方面有着良好的记录。