Great Race Eddies and Turbulence

在苏格兰西部的汝拉岛和斯卡巴岛之间坐落着以强烈的潮汐流和漩涡而闻名的科里弗瑞肯湾。不太为人所知的是“伟大的种族”，这是向西流动的壮观而狭窄的延伸。在每一次潮汐循环中，水被注入洛恩湾的开阔水域，其流速与亚马逊河的流量相当。毫不奇怪，这种流动对接收它的地区产生了深远的影响。模拟表明，在每一个潮汐周期中，在太阳的头部形成一对漩涡，一个顺时针的漩涡向北，一个逆时针的漩涡向南。这些漩涡在演变、相互作用和被新形成的漩涡取代的过程中持续了几个潮汐周期，所以伟大的种族实际上是洛恩湾的一个搅拌棒。我们计划利用这个非凡的自然实验室，在对高潮汐环境中的涡流、湍流和混合的理解方面取得进展，这将直接促进对这种环境进行数值模拟的能力的提高。该项目将使用一系列尖端技术和仪器。我们将向大竞赛及其漩涡中释放流动追踪水面漂浮物群，并开发通过移动电话网络快速监测它们的技术。一艘自主水下航行器（AUV）将在大竞赛下推进，以最小的尺度测量其湍流结构，而基于船只的调查将从上面描绘出更广阔的画面。这些技术中的每一种都将有助于我们对建筑的理解。一旦确定了伟大种族的本质和行为，关键任务将是了解能量如何在不同规模的漩涡中分布，以及随着距离漩涡源的距离增加，这种能量如何在不同规模之间“级联”。一个成功的数值模型将准确地反映这些特征。模型开发是这个项目的一个组成部分。从实地项目中获得的知识将直接用于评估和改进模型及其对太小而无法直接表示的运动的处理。最初的重点将放在“伟大种族”及其周边地区的本地模型上。学生将着眼于将在这种规模上获得的知识纳入更广泛的区域模型，有可能扩展到整个苏格兰西海岸。西海岸的模式既能在重要的小尺度上发挥作用，又能在更大的尺度上体现它们之间的相互联系，这将有助于对渔业、可再生能源开发等方面进行更明智的管理。

Between the islands of Jura and Scarba in western Scotland lies the Gulf of Corryvreckan, famous for its intense tidal flow and whirlpool. Less well known is the 'Great Race', the spectacular, narrow extension of that flow to the west. On each tidal cycle, water is injected into the open water of the Firth of Lorn at a rate comparable to the discharge of the Amazon. Not surprisingly, this flow has a profound impact on the region that receives it. Simulations suggest that a pair of eddies forms at the head of the Race during each tidal cycle, a clockwise eddy to the north and an anticlockwise eddy to the south. These eddies persist for several tidal cycles as they evolve, interact and are displaced by newly-formed eddies, so the Great Race is effectively a stirring rod for the Firth of Lorn. We plan to use this remarkable natural laboratory to make advances in the understanding of eddies, turbulence and mixing in highly-tidal environments which will feed directly into an improved ability to simulate such environments numerically. This project will use an array of cutting-edge technologies and instrumentation. We will release clusters of flow-tracking surface drifters into the Great Race and its eddies, developing techniques for rapidly monitoring them via a mobile phone network. An Autonomous Underwater Vehicle (AUV) will propel itself beneath the Great Race, measuring its turbulent structure on the smallest scales, while ship-based surveys will paint out the wider picture from above. Each of these techniques will contribute to our building understanding. Once the essential nature and behaviour of the Great Race have been determined the key task will be to understand how energy is distributed among eddies of different scales and how this energy 'cascades' between scales with increasing distance from the eddy source. It is these features that a successful numerical model will represent accurately. Model development is an integral part of this project. The knowledge gained from the field program will feed directly into evaluating and improving models and their treatment of motions that are too small to be directly represented. The initial focus will be on a local-scale model of the Great Race and its surroundings. A studentship will look at incorporating knowledge gained at this scale into wider area models, potentially extending to the entire west coast of Scotland. A west coast model that is skilful at the important small scales but also represents their interconnection at larger scales will allow better-informed management of fisheries, renewable energy development and more.