分层嵌套重叠网格自适应树结构动态组装方法  

A dynamic assembling method based on adaptive tree structure for hierarchical overset grids

作　　者：李晓东[1] 屈崑[1] 蔡晋生[1] 

机构地区：[1]西北工业大学航空学院,西安710072

出　　处：《航空学报》2017年第3期77-86,共10页Acta Aeronautica et Astronautica Sinica

基　　金：国家"973"计划~~

摘　　要：采用重叠网格可以有效地进行复杂流动的大规模数值模拟,特别是包含运动部件(如旋翼、投弹)的动态模拟。本文将树结构的自适应直角网格用于重叠网格组装过程中的切割和贡献单元的搜索,大大加快重叠网格的组装速度。通过二叉树自适应直角网格对物体外形进行离散,实现切割过程的快速定位;采用八叉树自适应直角网格对流场区域进行离散,高效地搜索贡献单元。使用基于壁面距离准则的重叠区域最小化方法和分层嵌套重叠策略,能提高重叠网格组装的效率和质量。对于具有运动部件的动态重叠网格问题,采用多个二/八叉树减少组装过程中信息更新的冗余计算,从而大幅度减少重叠网格组装的时间消耗。实际算例的重叠网格组装结果说明本文发展的重叠网格组装方法具有很高的计算效率,可以满足运动边界复杂流动问题的动态计算要求。The overset or chimera grid is an effective method for large-scale numerical simulation of aerodynamic problems with complex geometry, especially those with bodies in relative motion （such as the rotorcraft, store/aircraft separation）. The method of adaptive cartesian grids based on the tree structure is applied to perform fast hole cutting and donor searching in the overset grid assembly process. In this technique, the geometry is represented by adaptive cartesian grids of binary trees, and this can achieve quick locating in the hole cutting. Adaptive cartesian grids of octrees are used to decompose the flow field, making the donor searching efficient. By means of a minimal overlapping-domain approach and a hierarchical strategy for overset grids, which both employ the rule of wall distance, the efficiency and quality of overset grid assembly are improved. For dynamic problems of moving bodies, multiple binary trees and octrees are applied to decrease the redun- dant work of updating data in procedures of overset grid assembly, substantially reducing the time consumption. The test ca- ses demonstrate that the technique in this paper is computationally efficient and can be successfully employed to problems of multiple moving bodies.

关 键 词：嵌套重叠网格 二叉树 八叉树 自适应直角网格 动态网格 非定常流动 计算流体力学 

分 类 号：V211.3[航空宇航科学与技术—航空宇航推进理论与工程]