边界拟合坐标下流场计算模式

A2-D UNSTEADY FLOW COMPUTATIONAL MODEL IN BOUNDARY-FITTING COORDINATE SYSTEMS

流场数值模拟中，采用曲线坐标法准确模拟计算水域自然边界情形是当今研究的热点之一。本文借助于自然界中某些物理现象中其函数符合椭圆型且必然正交这一特性，建立了曲线坐标系，弥补在笛卡尔坐标系下二维流场模拟的边界贴合不足。应用本模式对我国某一河口水域的潮位和流场进行计算，结果表明：该模式具有物理意义清晰、稳定性良好、精度高等特点，模式对实际工程中流场模拟具有一定的应用价值。

To overcome the drawbacks of boundary-fitting in using the finite difference method to solve two-dimensimal unsteady flow equations in carttsian coordinate systems,a computational model in which boundary can be fitted accurately is established in this paper. Relying on orthogonality between streamline and iso-potential line of potential flow,a kind of orthogonal curvilinear coordinate system has been formed and used to transform arbitrary physical regiong to regular computational fields,and the size of formed curvilinear grid can be properly controlled according to the need of practical problems. In the generated new coordinate systems, two-dimensional unsteady flow has been simulated by using Alternation Direction Implicit Method (ADI).