面向三维激波问题的装配方法

Fitting algorithms for three dimensional flows with shock waves

给出了一种基于非结构动网格技术的三维激波装配方法。在该方法中,三维激波面由被标记为激波属性的网格点连接构成,标记为激波属性的网格点称为激波点。激波点具有两组参数分别代表激波的上下游,利用激波点上下游参数求解R-H关系式获得激波点运动速度。非结构动网格技术的使用允许激波大幅度运动,降低了对初始激波位置的要求。通过引入网格属性定义避免了对计算网格进行分区,增加了装配激波的灵活性。通过球柱体绕流问题验证了该三维装配方法的合理性,针对三维激波装配中比较困难的交点装配问题,通过对三维激波反射以及三维激波相交等算例进行研究找到了可用的三维激波交点运动速度的确定方法,保证了激波运动过程中交点运动与流场求解之间的相容性,获得了相应的装配结果。

A three dimensional shock-fitting technique based on unstructured dynamic grids is proposed in this work.In this algorithm,the shock front comprises a series of grid nodes labeled as shock points which have two states,with one representing the upstream of the shock wave and the other the downstream.The R-H relations are solved using these two states on a shock point to obtain the velocity of the shock point.The use of unstructured dynamic grids enables the shock front to move in a large range,decreasing the requirement of the initial shock position.The shocks are labeled by the definition of grid nodes rather than using internal boundaries between different subdomains to improve the flexibility of fitting shock waves.The reliability of the proposed algorithm is proven by a test case of hypersonic flow past a hemisphere-cylinder,followed by the study of three-dimensional shock reflection and shock-shock interactions to solve the relatively complex shock interaction problems in three dimensional shock-fitting.To guarantee the compatibility of the shock point motion and the flow field,usable methods to determine the velocity of three dimensional shock interaction points are obtained,therefore ensuring the achievement of convergence shock-fitting results by this shock-fitting technique.