gridgen使用手册.doc

gridgen使用手册 月4日 Gridgen 使用手册 一、概述 1、Gridgen的功能 Gridgen may be used to generate multi-block grids. A multi-block grid is created by dividing the overall region to be gridded into one or more sub-regions called blocks. Gridgen may be used to generate both 2D and 3D blocks. A 2D block consists entirely of surface cells while a 3D block contains entirely volumetric cells. The grid in each block may either be structured, unstructured, or hybrid. A structured grid consists entirely of hexahedral cells that have been arranged in an ordered IxJxK array. An unstructured grid consists of tetrahedral, pyramid, and prism cells having no implicit order. If all blocks contain structured grids, then the overall grid is called structured. When all blocks contain unstructured grids, then the overall grid is called unstructured. If the overall grid consists of both structured and unstructured blocks, the overall grid is called hybrid, a special type of unstructured grid. Gridgen数据的Hierachy 有四个级别： database：定义几何体外形。 connector: curve grid，曲线网格。 domain: surface grid，表面网格。 block: 体网格。 database就是geometry model of the object which a grid is to be generated。通常都是从CAD工具将几何模型导入Gridgen。注意，网格数据就已经包含了几何模型。更进一步，Gridgen并不要求database表示一个封闭的solid model。 connector是curve grid，在CAD概念中可以叫做composite curve，基本元素是segment，包括polyline、polycurve、conic、circle等几种类型。 画网格需要考虑的问题： 1.4.1 Define the Modeling Goals What specific results are required from the analysis? Are you just looking for general flow patterns or more detailed information about pressure, heat transfer, and separation locations in the flow field? What degree of accuracy is required? Are you looking for trends or absolutes? How much time do you have to complete the analysis? Do you have the time (both labor hours and computer) to analyze the complete system or can you obtain meaningful results by analyzing only the component of interest? 1.4.2 Identify Your Grids Constraints What types of grid topologies can your analysis software ha