用三维半人工瞬变法计算圆管内圆柱绕流

本文提出一种计算三维定常流动的半人工瞬变法,本方法的特点是直接利用流体力学的原始基本方程组进行数值计算。运动方程中的一个分量方程被用于计算压力,另外两个分量方程被加入人工瞬变项而成为人工瞬变方程,这两个人工瞬变方程被用于计算速度的两个分量,第三个速度分量则通过连续性方程进行计算得到。根据半人工瞬变方程组的特点和流动区域的特性,本方法采用半交错不等距非正交曲线贴体混合网格系进行数值计算,并利用质点导数差分格式使计算更简便。本文以圆管中不可压缩流体对圆柱的三维定常绕流问题为算例,具体画出计算用的半交错不等距非正交曲线贴体混合网格系,介绍三维半人工瞬变法的计算方法和步骤,并通过数值计算得到了此算例的计算结果。

Use Three Dimensional Method of Semi-False Transient to Compute Flow around Cylinder in Circular Pipe

A method of semi-false transient to compute three dimensional steady flow was presented.The feature of the method was that,the original basic equations in fluid mechanics were directly used to numerically compute.One component equation in motion equations was used to compute the pressure.Other two component equations added by false transient terms were become false transient equations.These two false transient equations were used to compute two component velocities.Third component velocity was obtained by means of continuity equation.According to the characteristics of semi-false transient equations and flow region,the semi-staggered non-equidistant non-orthogonal curvilinear mixed mesh system was adopted in the numerical computation of the method.Difference scheme of particle derivative was used in order to simpler compute.The problem of three dimensional steady incompressible flow around cylinder in the circular pipe was taken for an example of computation.The semi-staggered nonequidistant non-orthogonal curvilinear mixed mesh system was designed,the computational method and procedure about the method of three dimensional semi-false transient were described,and the computational results of the example were obtained by the numerical computation.