【摘要】 为了提高计算精度,本文研究了计算格式和网格技术。通过比较非结构网格下的NND格式、MUSCL格式、ENO格式及最小二乘格式的计算精度和波动,选择利用NND方法中的守恒变量法来建立非结构网格下的计算格式,通过改进NND方法中的限制器来提高计算精度和分辨率,计算结果比较显示出该格式具有很高的分辨率和计算精度。本文也研究了非定常网格自适应技术,计算给出了双马赫反射问题的新旧限制器及网格自适应计算结果比较,新限制器网格自适应后计算得到的滑移线出现了剪切涡现象,这表明,数值计算中取足够密的网格和构造高精度格式是非常必要的。更多还原

【Abstract】 The Investigation of numerical scheme and grid technique are presented in this paper. In order to solve the problem which higher precision scheme with unstructured/hybrid grid may generate serious disturbance, high order NND flux limiter method is presented. The results show that the present method is of high order and resolution. To improve the resolution, unsteady adaptive grid is adopted. The examples of numerical simulation of double MACH reflection are given with difference NND schemes and grids. The phenomenon of shear vortex of shear line is obtained in new NND scheme and unsteady adaptive grid. This shows that the very dense grid and high order scheme are necessary in numerical simulation. Finally the computational scheme is validated by some examples.更多还原