论文标题:非结构三角网格生成及其在二维水动力学模型中的应用
Unstructured Triangulation Grid Generation and It"s Application in 2D Hydrodynamics Model
论文作者
论文导师 陶建华,论文学位 硕士,论文专业 流体力学
论文单位 天津大学,点击次数 129,论文页数 56页File Size8934k
2005-01-01论文网 http://www.lw23.com/lunwen_853409527/
Delaunay triangulation;auto generation of point;grid smooth;Finite Volume Method
随着计算机技术的迅速发展,非结构网格生成技术在近二十年来得到了很大发展。它舍去了网格节点的结构性限制,节点和单元的分布是任意的,因而能较好地处理不规则边界,很容易控制网格单元的大小与节点密度。另外,非结构网格一般能够自动生成,一旦指定网格的分布,即可自动生成网格,无须分块和用户的干预。本文基于Delaunay三角化的思想实现了二维非结构化数值网格自动生成,改进了新节点插入位置的判断方法,并利用此方法简化Delaunay三角划分过程。同时,扩充了A.Bowyer等人在Delaunay三角剖分算法中所用的数据结构,使之能够更加方便、快速地执行插入、删除、搜索等数据处理操作,提高了网格生成速度。采用网格密度传播的方法,能够很好地处理局部细节尺寸相对于整体尺寸很小的复杂形体的网格划分和局部加密。给出了非凸参数区域情况下,区域外的三角形删除的几种算法,以确保区域边界的正确三角剖分。对生成的网格进行了优化。本文所用方法能够适应二维复杂形状的几何边界,网格的疏密程度能够根据用户的要求任意调解。利用Visual C++编制了视窗操作系统下的二维网格自动生成应用程序。用有限体积法在三角形网格上对二维水动力学模型离散,对渤海潮流进行模拟。实例应用分析表明,本文的数值网格生成技术和有限体积方法相结合用于求解具有复杂几何边界区域内的流体流动问题能取得很好的结果。
Unstructured grid generation techniques have been made great progress in recentyears, especially with the development of computer science. Without the restrictionsof the structure of gird nodes, the nodes and elements of unstructured grids can bedistribute arbitrarily, so they are applicable to very complex geometrical domains.Once the distribution of boundary nodes is given, unstructured grids usually can begenerated automatically. In this paper, the unstructured gird is generated with numerical method based onthe conception of Delaunay Triangulation. Meanwhile, improvements have been madeto the date structure used in Delaunay triangulation pioneered by A.Bowyer, whichenable the method to insert, delete, search date more conveniently and quickly.Mesh-generating speed is also improved. It has the power of generating good qualitygrids for complicated shapes whose detail sizes are much smaller than that of theoverall shape and forming denser grids in detail places, based on domain grid gradingpropagation. Some methods are given to delete the unprotruding domain ,smooththe grid and resume the losing boundary. This method can adapt a random complexgeometry boundary. And the density of the generated grid can be adjusted accordingto the restriction of the size. An automatic 2D mesh-generating program is madeunder windows system using Visual C++.The two dimensional hydrodynamics model is solved numerically with FiniteVolume Method based on unstructured triangulation grid. Numerical experimentsshow that the numerical model is effective to compute the tidal current in the coastalarea with complex boundaries.
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