Collaborative Research: Quantifying Stratified Turbulence in Estuaries

理解强层结中的湍流混合是流体动力学中一个长期存在的基本问题。建议的研究的目标是确定负责河口混合在大梯度理查森数的机制，并在此制度下测试湍流参数化。这一领域的大多数高质量数据来自实验室测量和直接数值模拟。湍流通量和耗散率的现场测量对于了解湍流在物理学相关尺度上是必不可少的。河口是分层湍流的极好实验室，因为它们将联合收割机强分层与强潮汐力结合在一起。测量，模拟和分析将阐明分层湍流和河口动力学。在两个河口的混合，预计将由明显不同的机制驱动进行测量。传感湍流的移动的阵列（MAST）测量将通过三维雷诺平均数值模拟来补充，这将使测量结果与更大规模的河口动力学背景相结合，并允许对湍流参数化进行评估。MAST是一种新的现场仪器平台，可以以前所未有的空间和时间分辨率解决关键的湍流量。这些目标将与湍流通量，耗散率和长度尺度的MAST测量进行检查，具有高的空间和时间分辨率，在固定和进行中的模式，从而允许长时间序列测量和空间变异性的量化。三维数值模式作为河口海岸环境管理工具发挥着越来越重要的作用。更广泛的影响也将包括一个明确的组成部分，沟通本研究的影响，以改善河口和沿海环流模型的跨学科科学和管理应用的约束关闭参数化。

Understanding turbulent mixing in strong stratification is a longstanding fundamental problem in fluid dynamics. The objectives of the proposed study are to determine the mechanisms responsible for estuarine mixing at large gradient Richardson number and to test turbulence parameterizations in this regime. Most high-quality data in this regime have resulted from laboratory measurements and direct numerical simulations. Field measurements of turbulent fluxes and dissipation rates are essential to understand turbulence at geophysically relevant scales. Estuaries are excellent laboratories for stratified turbulence because they combine strong stratification with strong tidal forcing. The measurements, simulations, and analyses will elucidate both stratified turbulence and estuarine dynamics. Measurements are conducted in two estuaries where the mixing is expected to be driven by distinctly different mechanisms. The Mobile Array for Sensing Turbulence (MAST) measurements will be complemented by three-dimensional Reynolds-averaged numerical simulations, which will place the measurements in context with the larger scale estuarine dynamics and permit evaluations of the turbulence parameterizations. The MAST is a new field instrument platform that can resolve key turbulent quantities with unprecedented spatial and temporal resolution. The objectives will be examined with MAST measurements of turbulent fluxes, dissipation rates, and length scales with high spatial and temporal resolution in fixed and underway modes, thus permitting both long time-series measurements and quantification of spatial variability. Three-dimensional numerical models play an increasingly important role as management tools in estuarine and coastal environments. The broader also impacts will include an explicit component to communicate the implications of this study to improve the turbulence-closure parameterizations in estuarine and coastal circulation models for interdisciplinary science and management applications.