【作者】 刘飞；

【导师】 钟易成；

【作者基本信息】 南京航空航天大学 ， 流体机械及工程， 2009， 硕士

【摘要】 非结构化网格对复杂模型具有较强的适应性,因此被广泛地应用到CFD计算当中。本文采用Delaunay算法,利用面向对象的编程技术开发了一套非结构网格生成软件。该网格生成软件可以进行二维平面、三维曲面、三维实体非结构化网格生成以及半结构化网格生成。并且成功地生成了涡轮冷却叶片非结构化网格。论文详细研究了Delaunay三角剖分的关键问题以及相应的解决方案,包括插点算法、浮点运算误差处理、网格优化技术、边界恢复问题。其中边界恢复问题采用了将一致边界恢复和约束边界恢复相结合的方式,实验证明此种方法能够较好地完成三维网格边界恢复工作,对复杂模型具有一定的适应性。在Delaunay三角剖分算法的基础上,通过引入黎曼度量矩阵完成了曲面非结构网格生成,并给出了黎曼空间下的近似外接圆准则。该方法能够对复杂曲面生成高质量的非结构网格。通过物面映射法生成半结构化网格,并与外层非结构化网格对接形成了混合网格。根据Delaunay方法的自身特点设计了合理的数据存储结构以及几何拓扑体系;运用C++语言开发了实现非结构化网格生成的各功能模块。并且将该网格生成体系与已有的几何造型体系进行了有机的融合,使得对于特定模型能够快速地生成几何模型和计算网格。更多还原

【Abstract】 For complex model unstructured grid has preferable adaptability, and which is widely applied to the CFD. In this paper, we use Delaunay triangulation as base algorithm, and object-oriented programming as technology to develop a set of unstructured grid generation software. The grid generation software can be applied to two-dimension plane, surface, three-dimension entity’s unstructured grid generation, as well as semi-structured grid generation. And the adoption of the software is successfully generated unstructured grid cooling turbine blade.This paper study the Delaunay triangulation of the key issues and corresponding solutions, including the insertion point algorithm, floating-point error handling, mesh optimization techniques, the boundary recovery. And the combination of conforming boundary recovery and constrained boundary recovery is used to deal with boundary recovery. Experiment proves that the method can complete three-dimensional grid boundary recovery preferable, and has a certain degree of adaptability to complex model. Based on the algorithm of Delaunay triangulation, introduce a metric tensor to complete the surface triangulation. And the definition of the cavity in a Riemannian space is given. The examples demonstrate the advantages of the surface triangulation software which indicating that dealing with complex model and high quality. Surface mapping method is adapted for generating semi-structured grid. Joining the grids near the wall and in the other fields into hybrid grids is the final step for generating hybrid grids. And has carried on this mesh generation system and the existing geometric modeling system the organic fusion, enables to be able to produce the geometric model and the computation grid fast regarding the specific model.According to the Delaunay method’s inherent characteristics designed the rational data storage structures and geometric topology system. The use of C + + language development unstructured grid generation for achieving the various functional modules. And has carried on this mesh generation system and the existing geometric modeling system the organic fusion, enables to be able to produce the geometric model and the computation grid fast regarding the specific model.更多还原