An unstructured-grid, finite-volume, nonhydrostatic, parallel coastal ocean simulator
An unstructured-grid, finite-volume, nonhydrostatic, parallel coastal ocean simulator
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DOI：
10.1016/j.ocemod.2006.03.006
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发表时间：
2006-01-01
期刊：
影响因子：
3.2
通讯作者：
Street, R. L.
中科院分区：
文献类型：
--
作者：
Fringer, O. B.;Gerritsen, M.;Street, R. L.
本文提出了一种有限体积法，在非结构化交错z层网格上采用Boussinesq近似求解三维非静力Navier-Stokes方程，其目标是模拟沿海海洋中的非静力过程，网格分辨率为几十米。特别是，该代码已经开发，以模拟非线性，非静水内波场在沿岸的海洋。该方法是基于Casulli开发的配方，在自由表面和垂直扩散是半隐式的，从而消除与表面重力波和垂直扩散项的稳定性限制。动量方程中的其余项用二阶Adams-Bashforth方法显式离散，而压力校正方法用于非静水压力，以实现整体二阶时间精度。动量平流是用欧拉离散化来完成的，该离散化在不包含自由表面的单元中保持动量，标量平流以确保连续性的一致性的方式离散化，从而使用在局部和全局基础上保持体积的速度场来确保局部和全局质量守恒。的非流体静力学压力场有效地解决了使用块Jacobi预条件，而稳定性是有限的内部重力波速度和垂直平流的动量，应用程序需要相对较小的时间步长，由于精度或稳定性的限制，有效地运行在并行计算机上，因为本制剂是写完全与消息传递接口（MPI）。ParMETIS库是为了实现负载平衡的并行分区，最大限度地减少处理器间的通信，网格被重新排序，以优化每个处理器的性能，通过限制高速缓存未命中，同时访问内存中的数组。测试案例表明，代码的能力，有效地和准确地计算非流体静力锁交换和内波在理想化以及真实的域，我们评估的并行效率的代码使用多达32个处理器。(c)2006爱思唯尔有限公司保留所有权利。
A finite-volume formulation is presented that solves the three-dimensional, nonhydrostatic Navier-Stokes equations with the Boussinesq approximation on an unstructured, staggered, z-level grid, with the goal of simulating nonhydrostatic processes in the coastal ocean with grid resolutions of tens of meters. In particular, the code has been developed to simulate the nonlinear, nonhydrostatic internal wave field in the littoral ocean. The method is based on the formulation developed by Casulli, in that the free-surface and vertical diffusion are semi-implicit, thereby removing stability limitations associated with the surface gravity wave and vertical diffusion terms. The remaining terms in the momentum equations are discretized explicitly with the second-order Adams-Bashforth method, while the pressure-correction method is employed for the nonhydrostatic pressure in order to achieve overall second-order temporal accuracy. Advection of momentum is accomplished with an Eulerian discretization which conserves momentum in cells that do not contain the free surface, and scalar advection is discretized in a way that ensures consistency with continuity, thereby ensuring local and global mass conservation using a velocity field that conserves volume on a local and global basis. The nonhydrostatic pressure field is solved efficiently using a block-Jacobi preconditioner, and while stability is limited by the internal gravity wave speed and vertical advection of momentum, applications requiring relatively small time steps due to accuracy or stability constraints are run efficiently on parallel computers, since the present formulation is written entirely with the message-passing interface (MPI). The ParMETIS libraries are employed in order to achieve a load-balanced parallel partitioning that minimizes interprocessor communication, and the grid is reordered to optimize per-processor performance by limiting cache misses while accessing arrays in memory. Test cases demonstrate the ability of the code to efficiently and accurately compute the nonhydrostatic lock exchange and internal waves in idealized as well as real domains, and we evaluate the parallel efficiency of the code using up to 32 processors. (c) 2006 Elsevier Ltd. All rights reserved.