跨音速非定常流动的Euler方程隐式解

 在随时间变化的贴本坐标系中给出求解非定常Euler方程的连续通量分裂法。在此基础上建立了可用于跨音速非定常流动的Euler方程隐式求解法。采用特征向量变换,可在保证原方程组离散化精度的条件下使计算大为简化。针对振动翼绕流特点建立了固连于物体的动坐标与固定坐标间的关系。数值计算在动坐标中进行,既简化网格生成又保证在物面上满足边晃条件。对NACA64A-10冀型绕1/4弦点做简谐俯仰振动的非定常气动力进行了计算,给出了与实验结果基本相符的计算结果。此外,还给出翼型做沉浮及同时进行沉浮与俯仰二自由度振动的非定常气动力的计算结果。

AN IMPLICIT DIFFERENCE SCHEME OF EULER EQUATION FOR UNSTEADY TRANSONIC FLOW

A continuous flux splitting method for unsteady Euler equations based on time-dependent body fitted coordinates is given. And with this method, an implicit difference equation for solving the unsteady transonic flow with Euler equations is established. In order to reduce the computer time for solving the block-matrix equations, the characteristic matrix transformation is used. This transformation does not change the discrete order of the equations but the CPU for solving the matrix equations can be reduced greatly. The numerical computation is made in the moving coordinates, so that not only the boundary conditions are kept on the real body surface, but the time-dependent body fitted coordinates are built in a very simple way as well. The NACA64A-10 airfoil which oscillates in pitching about its 1/4 chord point is computed. The computed results are in good agreement with the experiment data. Besides, some calculated results for the airfoil oscillating in heaving and both in heaving and pitching are also shown in the paper.