计算物理 ›› 1985, Vol. 2 ›› Issue (3): 368-374.

• 论文 • 上一篇    下一篇

解双曲型方程组的分离系数矩阵差分法

张鲁民   

  1. 中国气动力研究与发展中心
  • 收稿日期:1984-10-18 出版日期:1985-09-25 发布日期:1985-09-25

THE SPLIT COEFFICIENT MATRIX (SCM) FINIT DIFFERENT METHOD FOR HYPERBOLIC EQUATIONS

Zhang Lu-min   

  1. China Aerodynamic Researh anb Development Centre
  • Received:1984-10-18 Online:1985-09-25 Published:1985-09-25

摘要: 分离系数矩阵(SCM)差分方法是近年来发展的一种基于特征理论的数值方法,该方法将双曲型方程组系数矩阵,利用相似变换,按照特征值的正负构造成SCM方程,然后,合理地选择适合于SCM方法的二阶单向差分格式,能显示出流场中每点的特征值的方向和大小,也就是对于含正特征值的项用向后差分算子,并乘以正特征值,而含负特征值的项用向前差分算子,乘以负特征值,这比以往的差分计算具有合理的物理意义。本文参考文献[1]导得了三维非对称头部绕流的分离系数矩阵方法,不论内点或特殊点都是分离系数矩阵形式,除此之外,还将SCM方法推广于后身的超音速区域。通过计算表明,在头部区采用局部Δt步长,能加速非定常流的收敛,对于后身超音速区,该方法用较少的网格点,仍获得较高的精度。

Abstract: SCM finite difference method for solving inviscid subsonic, transonic and supersonic flow over spherical cone is presented. This method is based on the mathematical theory of characteristics.In the SCM approach these coefficients are split according to the sign of the chara-oteristic slopes. The split coefficients are multiplied by appropriate one-sided. F orwardiffe-rences are associated with negative characteristic stopes, while baokward diflerchces are associated with positive slope values.In the SCM technique the governing Euler equations are solved by a secondorder accurate finit difference elgori thm in a predictor-corrector sequence. To maintain Secondorder spatial accuracy for the one-sided derivatives associated with the split coefficients the discretization formulas alternate between two-point and three -point approximation.The numerical example of the blunt spherecones have been worked in this paper and compared with Conventional finite difference to demonstrate good accuracy of SCM in rate mesh.