高精度TVD有限差分格式的自由梯度条件

1自由流条件守恒性气动方程组的高精度TVD有限差分格式一般通过使用通量限制器加入非线性的人工粘性来构成。在曲线坐标系中，通量限制器比较的两个因子与各自所在单元的界面雅可比转换行列式相关。为了消除畸变网格单元界面雅可比转换行列式的变化对通量限制器比较结果的影响，本文提出了高精度TVD格式的自由梯度性质，并分别就Osher和HartenTVD格式讨论了同时满足自由流和自由梯度的度量张量计算方法，使高精度TVD格式在畸变网格上得以实现。任意曲线坐标系中守恒型二维欧拉方程表示为其中，E、F为笛卡尔坐标系中的通量；J为坐标变…

THE FREE-GRADIENT OF TOTAL VARIATION DIMINISHING FINITE DIFFERENCE CELL-CENTERED SCHEMES WITH HIGH ORDER OF ACCURACY

The free-gradient is proposed for cellcentered total variation diminishing finite difference schemes of inviscid aerodynamic equations with high order of accuracy to eradicate the negative effects of the mesh skewness on the flux limiter. This paper demonstrates that it can satisfies the free-stream and free-gradient simultaneously and keeps the accuracy order of the schemes by assigning the Jacobe of transformation on the cell surfce as 1 for Harten and osher-Chakravarthy schemes. It also shows that Yee-Harten schemes do not satisfy the free-gradient, thus a modification is conducted to make them work better on skewed meshes.