毕业论文--后台阶流场无网格法气体流场数值模拟.doc

本科毕业论文( 20 12 届) 题目后台阶流场无网格法气体流场数值模拟学院专业班级学号学生姓名指导教师完成日期 2012/5/17 杭州电子科技大学本科毕业论文摘要无网格法的研究历史较短,在严格的数学论证、计算效率、边界条件处理和工程应用实例等方面还不能与成熟的有限元法相媲美,更未形成有效的通用软件,但是与有限元等基于网格的值方法相比,无网格法具有许多独特的优势。实际工程中大量存在几何形状不规则或急剧变化的区域,这些区域内流动的显著特点是流动边界层脱离,出现大尺度涡,速度梯度和脉动加大,导致集中的能量损失,详细获取其流场的信息具有实际的意义。后台阶流即属此类流动,常被用作算例来检验算法精度和稳定性。但是对于采用无网格法对于流场的数值模拟研究尚处于起步阶段,相对于有网格法,采用无网格法进行后台阶流场的数值会呈现新的规律。本文就是尝试采用径向基函数为基础的无网格化法,通过软件程序来运行无网格化法进行数值模拟,然后与有网格化法( Fluent )的数值模拟比较,分析区别和结果,做出评估。首先本文对无网格法的产生和发展做一些简单的介绍;其次简单介绍无网格法的原理和分类,并对其中的几种典型无网格法进行了大体的介绍,为后面了解径向基函数法即配点型无网格法做一个铺垫;再次,有网格化法主要采用有限差分法,本文将对有限差分法的原理和步骤进行简单的介绍;然后用 Fluent 处理一个简单的工况;最后将其与无网格法得到的结果进行一个简单的比较,然后做出分析和评价。关键词: 无网络法;速度梯度;径向基函数;有限差分法; Fluent ;配点型无网格法。杭州电子科技大学本科毕业论文 ABSTRACT The history of meshless method is short, in the strict mathematical demonstration, computational efficiency, boundary conditions and engineering application ,it is also parable with the mature finite element method. It does also not form an effective general-purpose pared to grid-based value method,such as finite element methed, meshless method has many unique advantages. There are a lotof irregular geometry or dramatic changes in the region in Practical engineering, the distinctive feature of these regionsis that the flow boundary layer has detached,then the large-scale es along, the velocity gradient and pulse increase, resulting ina centralized energy loss,so obtaining the flow field information isof practical significance. The backward-facing step flow is such a flow, often used as examples to test the algorithm accuracy and stability, But for the meshless method for numerical simulation of the flow field is still in its infancy relative to the grid method, meshless method steps of the value of the flow field will show the new laws. This article is to try using radial basis function based meshless method for numerical simulation by using the software program , and par e the result with the grid method (by using the Fluent) numerical simulation, at last, analys e