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 Street许多计算和数值工具将被合成，以产生一个创新的和强大的沿海海洋模拟工具。该项目的主要目标是采用数值大涡模拟，在非流体静力和地形跟踪表示必不可少的条件下，对沿海海洋的运动和迁移进行准确预测。该模型应能处理从自由表面到河床的所有过程，以便能够模拟从表面波到内波到沉积物运动的整个范围。第二个目标是应用最好的算法来创建一个模拟代码，该代码能够以高分辨率表示物理过程，并且能够在多处理器并行计算机上实现非常高的速度。 该项目代码将从现有的非结构网格上的非静力自由面流动的半隐式数值代码发展而来。该代码是基于三维非定常Navier-Stokes方程，并利用半隐式算法，是强大的，稳定的，非常有效的。然而，现有的代码是为串行机器开发的，缺乏沿海海洋应用的一些重要元素，例如，标量或物质输运模块、用于大涡模拟的最先进的子滤波器尺度模型以及测深或海岸边界的高分辨率处理。这项工作的重点是并行化的代码，并安装适当的算法，以满足需要准确地表示物理和需要产生一个快速和强大的生产代码的沿海地区。一个基本的概念将是无缝地嵌入沿海模拟在更大规模的模拟，使自然边界条件将适用于整个域。没有人工设备将被用来过滤模拟，以避免代码不稳定性或边界反射。将在水平面上采用非结构化网格，以便准确地表示水深和海岸特征，这需要从一个子域到另一个子域的网格密度有很大变化。将采用复合网格法，在水深测量上建立一个地形跟踪高分辨率网格，并与内部区域相连接。已计划对完成的代码进行两次具体应用。两者都涉及内潮的非静力演化。第一个是在加州的蒙特利湾，在蒙特利峡谷底部，预计会形成孤立子，内部潮汐信号会增强。第二个是在马马拉湾，夏威夷，高振幅和非线性的内潮汐观察和有关键问题要回答这些波的性质和他们的行为在海湾。对这项工作的贡献包括：高性能：使用MPI并行实现，消息传递接口;优化的非结构网格，非静水压力的3D并行求解器;代码功能：基于TVD方法的非结构网格的精确平流;非静水大涡模拟，具有充分验证的速度估计方法，用于子滤波器尺度运动;最先进的网格生成[水平方向非结构化]，用于精确解析复杂的水深测量和海岸边界以及嵌入式海底网格;使用半隐式处理的自由表面;以及生产型：详细的用户手册，其中说明了海岸-海洋尺度模拟代码的使用