ELCIRC源程序代码分析

开放源程序代码ELCIRC是采用基于水平向无结构网格、垂向z坐标体系和半隐格式的欧拉-拉格朗日有限体积/有限差分方法来解浅水方程。研究了ELCIRC中除控制方程组求解以外的部分,分析了源程序在插值计算、拓扑结构、定解条件、分层信息和干湿法等技术上的具体操作,尤其是对欧拉拉格朗日模型特有的逆向追踪算法做了详细阐述。同时讨论了一些细节问题,在不恰当的地方给出一些参考和建议,避免小数做分母、相近数相减引起的较大误差。然而,这些经过实际应用的算法原理,可以为我们开发水动力学模型提供有价值的参考。

Algorithm of ELCIRC Source Code

Open-source code ELCIRC(Eulerian-Lagrangian CIRCulation) solves the shallow water equations using a semi-implicit Eulerian-Lagrangian finite volume/finite difference method with horizontally unstructured grids and vertically unstretched z-coordinates. ELCIRC source code aside from the governing equation solution is analyzed in this paper. The operation of interpolation,topological structure,definite condition,hierarchy information,and wetting and drying method are described in detail. Backtracking,as the key technology of ELCIRC,is expounded comprehensively. Moreover,some detailed problems are discussed,and a few references and suggestions are given to avoid the errors caused by similar number subtraction and by employing small number as the denominator. ELCIRC has been applied in practice and could serve as a valuable reference for developing hydrodynamic models.