摘要
物体从相互接触的状态分离时会导致流场拓扑结构的改变,针对拓扑结构改变过程提出了一种非结构重叠网格算法。该方法主要包括"洞边界"自动判定、重叠区形成和流场信息交换三个方面的关键问题。针对三维问题提出了判定洞边界的"曲面判定方法";对于重叠区待插值的网格节点建立了"动态叉树"贡献单元搜索方法。洞边界上待插值点的流场参数通过插值方法从其贡献单元上得到。弹丸从炮口发射的过程中,由于弹丸与炮管的分离导致了流场拓扑结构变化,而当炮口带有制退器时将使流场的边界条件更加复杂。利用非结构重叠网格方法对弹丸从带有炮口制退器的火炮中发射过程进行了数值模拟,分析了初始冲击波形成和发展过程,详细描述了运动弹丸对膛口流场的影响。本文提出的算法将能够有效地应用到航空、航天以及兵器技术领域的研究中,特别是物体分离过程导致的流场拓扑结构改变问题。
To solve the problems which contain changes of topological structure,an OUG（overset unstructured grids） method is improved in this paper.This method contains the following three important parts： the automatic judging of hole-boundaries,the forming of overlapped areas and the transferring of flow field information.The ＂curved surface judging method＂ was advanced to build the hole-boundaries.The ＂Dynamic Quadtree/Octree＂ search algorithm is proposed to search the donor cells of the nodes which locate on the hole-boundary.Flow parameters of non-active nodes on the hole-boundary are calculated by interpolating from the donor cells.In a launching process,the relative sliding and departing takes place between a bullet and a barrel contacting with each other,and therefore topological structure of the flow field changes,when a muzzle brake is fixed on the muzzle,the flow field of power gas changes to be more complex.This OUG method is applied to simulate the process of a projectile being launched from cannon which has a muzzle brake.The process of precursor shock wave being formed is clearly shown in the simulation results.The influences of the projectile to the muzzle flow field are all described in detail.This method is proved powerful to solve the problems of moving bodies which are in contact with each other separating from each other,especially the process of topological structure changing during the departing period of the moving bodies.
出处
《空气动力学学报》
EI
CSCD
北大核心
2011年第1期52-58,共7页
Acta Aerodynamica Sinica
关键词
流场
分离
拓扑结构
非结构重叠网格
炮口制退器
运动边界
flow field
depart
topological structure
Overset Unstructured Grids（OUG）
muzzle brake
moving boundary
