ITR/AP (GEO): High Resolution Parallel Coastal Ocean Modeling

ITR/AP (GEO)：高分辨率平行沿海海洋建模

• 批准号: 0113111
• 负责人: Robert Street
• 金额: $ 48.22万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-01-01 至 2005-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0113111&HistoricalAwards=false
• 关键词: ITR; AP; GEO; Resolution; Parallel

0113111 Street A number of computational and numerical tools will be synthesized to produce an innovative and powerful coastal ocean simulation tool. The primary goal of the project is to employ numerical large-eddy simulation to generate accurate predictions of motions and transport in coastal oceans under conditions when a non-hydrostatic and terrain-following representation is essential. The model should be able to handle all processes from the free surface to the bed so that the whole range from surface waves through internal waves to sediment motions can be simulated. The second goal is to apply the best algorithms available to create a simulation code that is capable or representing the physical processes at high resolution and capable of very high speed on multiple processor parallel computer. The project code will evolve from an existing semi-implicit numerical code for nonhydrostatic free-surface flows on unstructured grids. The code is based on the three-dimensional unsteady Navier-Stokes equations and utilizes a semi-implicit algorithm that is robust, stable, and very efficient. However, the existing code was developed for serial machines and lacks a number of important elements for the coastal ocean application, e.g., a scalar or material transport module, state-of-the-art subfilter-scale models for large-eddy simulation, and a highly-resolved treatment of the bathymetric or coastal boundaries. The focus of this work is to parallelize the code and install appropriate algorithms to meet both the need to represent the physics accurately and the need to produce a fast and robust production code for the coastal zone. A fundamental concept will be to seamlessly imbed the coastal simulations in larger-scale simulations so that natural boundary conditions would be applied around the entire domain. No artificial devices would be used to filter the simulations to avoid code instabilities or boundary reflections. The unstructured grid will be employed in horizontal planes allowing accurate representation of bathymetric and coastal features, which require severe changes in grid density from one subdomain to another. The composite grid method will be employed to fit a terrain-following highly resolved grid over the bathymetry and linked to the interior domain. Two specific applications of the completed code are planned. Both involve nonhydrostatic evolution of internal tides. The first is in Monterey Bay, California, where solitons are expected to form and the internal tide signal is intensified in the bottom of the Monterey Canyon. The second is in Mamala Bay, Hawaii, where high-amplitude and nonlinear internal tides are observed and there are key questions to be answered about the nature of these waves and their behavior in the Bay. The contributions on this work include: High performance: Parallel implementation using MPI, the message passing interface; Optimized unstructured-grid, 3D parallel-solver for the nonhydrostatic pressure; Code Features: Accurate advection based on the TVD method for unstructured grids; Nonhydrostatic large-eddy simulation with a fully-validated velocity estimation method for subfilter-scale motions; State-of-the-art grid generation [unstructured in the horizontal] for accurate resolution of complex bathymetry and shore boundaries and an embedded bottom following grid; Free surface using a semi-implicit treatment; and Production-style: Detailed users' manual that illustrates the use of the code for coastal-ocean scale simulations

0113111街将综合一些计算和数值工具，以产生一个创新和强大的沿海海洋模拟工具。该项目的主要目标是利用数值大涡模拟，在非静力和地形跟踪表示必不可少的条件下，产生对沿海海洋运动和运输的准确预测。该模型应该能够处理从自由面到床面的所有过程，以便能够模拟从表面波到内波再到泥沙运动的整个范围。第二个目标是应用现有的最好的算法来创建能够或能够在多处理器并行计算机上以高分辨率表示物理过程并且能够非常高速的模拟代码。该项目代码将从非结构网格上非静力自由表面流动的现有半隐式数值代码演变而来。该程序以三维非定常N-S方程为基础，采用了一种稳健、稳定、高效的半隐式算法。然而，现有的代码是为串行机开发的，缺乏一些适用于沿海海洋应用的重要元素，例如标量或材料传输模块、用于大涡模拟的最先进的子过滤器尺度模型，以及对水深测量或海岸边界的高度分辨率处理。这项工作的重点是并行代码和安装适当的算法，以满足准确表示物理的需要和为海岸带产生快速和健壮的生产代码的需要。一个基本的概念是将海岸模拟无缝地嵌入更大规模的模拟中，以便在整个区域周围应用自然边界条件。不会使用任何人工设备来过滤模拟，以避免代码不稳定或边界反射。非结构化网格将被用在水平面上，允许精确地表示水深和海岸地物，这需要从一个子域到另一个子域的网格密度的严重变化。复合网格方法将被用来拟合地形跟踪的高分辨率网格在水深测量上，并连接到内部区域。计划对完成的代码进行两个具体的应用。两者都涉及到内潮的非静力演化。第一次是在加利福尼亚州的蒙特利湾，那里预计会形成孤立子，内部潮汐信号在蒙特利峡谷底部增强。第二个是在夏威夷的马马拉湾，在那里观测到了高幅度和非线性的内潮，关于这些波的性质和它们在海湾的行为有一些关键问题需要回答。这项工作的贡献包括：高性能：使用MPI并行执行，消息传递接口；针对非静力压力的优化非结构网格，3D并行求解器；代码特点：基于非结构网格的TVD方法的精确平流；对子过滤器尺度运动的完全有效的速度估计方法的非静力大涡模拟；最先进的网格生成[水平无结构]，用于精确解析复杂的水深测量和岸边边界以及嵌入的海底跟随网格；自由表面使用半隐式处理；以及生产型：详细的用户手册，说明了沿海-海洋尺度模拟代码的使用