共查询到16条相似文献,搜索用时 78 毫秒
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论文给出了PEBI网格的有关概念,对三维PEBI网格生成进行了分析,提出一个定理并进行了证明。随之提出一种简捷有效的生成算法-控制球算法。最后给出了三维PEBI网格例子,验证了该算法的正确性和有效性。算法可以直接用于油藏模拟计算,并可推广到其它领域。 相似文献
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基于PEBI网格的油藏数值模拟能够更准确地模拟地下油藏流动,模拟过程中主要是求解以PEBI网格为差分单元的有限差分方程。提出采用谱算法优化PEBI网格节点的编号来减少差分方程中系数矩阵的带宽,以节约计算时间和数据存储量。首先计算网格按初始编号所形成的邻接矩阵及其Laplacian矩阵,然后通过计算Laplacian矩阵的特征值和特征向量得到Fiedler特征向量,最后对Fiedler特征向量进行排序,并根据排序后的向量对PEBI重新编号。最后通过实验验证了谱算法在PEBI网格编号优化中的有效应用。 相似文献
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针对分段线性复合形约束条件下的三维限定Voronoi剖分问题,提出一种细化算法.首先证明了分段线性复合形中的元素在最终生成的三维限定Voronoi网格中可表示为Power图结构;受此启发,提出了对限定线段平面片分别进行一维二维Power图细化以实现三维限定Voronoi 网格生成的细化算法,并且证明了该算法对于任意分段线性复合形收敛.最后通过实例验证了文中算法的有效性. 相似文献
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一种网格和节点同步生成的二维Delaunay网格划分算法 总被引:1,自引:0,他引:1
应用Lawson算法对网格的Delaunay性质进行维护,利用单元尺度场控制生成网格的疏密分布;找到任一不满足尺度场要求的单元,在其可插度最大的边上按一定法则插入新节点,加密网格,实现内节点的生成与网格划分同步进行.该算法避免了搜寻包含三角形的过程,提高了效率.通过多次划分实验表明,该算法的时间复杂度约为O(N1.2).同时,由于在不满足单元尺寸要求的单元边上插入新节点,直接对单元的边长进行控制,使得网格的质量和自适性更加良好. 相似文献
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二维约束Voronoi网格构造及其尺寸、质量控制 总被引:3,自引:3,他引:3
给出二维约束Voronoi网格的有关概念,分析了约束线段在二维Voronoi网格存在的条件,提出了一种二维约束Voronoi网格构造算法;并对二维约束Voronoi网格的尺寸和质量控制进行了研究;最后给出了实例以说明算法的有效性.该算法计算快速,适应性广,在诸多领域具有广泛的应用前景. 相似文献
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针对二维平面问题,通过曲率计算和基于中轴理论的邻近特征计算控制区域边界曲线的离散;修改经典的前沿推进算法,利用边界驱动的单元尺寸控制方式在区域内部布置疏密过渡合理的三角网格;结合几何和拓扑策略提升网格质量。实验表明,上述算法可生成单元质量高、尺寸过渡合理的计算网格。 相似文献
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Constrained delaunay triangulations 总被引:13,自引:1,他引:13
L. Paul Chew 《Algorithmica》1989,4(1):97-108
Given a set ofn vertices in the plane together with a set of noncrossing, straight-line edges, theconstrained Delaunay triangulation (CDT) is the triangulation of the vertices with the following properties: (1) the prespecified edges are included in the triangulation, and (2) it is as close as possible to the Delaunay triangulation. We show that the CDT can be built in optimalO(n logn) time using a divide-and-conquer technique. This matches the time required to build an arbitrary (unconstrained) Delaunay triangulation and the time required to build an arbitrary constrained (non-Delaunay) triagulation. CDTs, because of their relationship with Delaunay triangulations, have a number of properties that make them useful for the finite-element method. Applications also include motion planning in the presence of polygonal obstacles and constrained Euclidean minimum spanning trees, spanning trees subject to the restriction that some edges are prespecified.An earlier version of the results presented here appeared in theProceedings of the Third Annual Symposium on Computational Geometry (1987). 相似文献
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近年来兴起的多边形有限元方法,在有限元计算中采用多边形单元划分网格,不仅可以更好地适应求解区域的几何形状,而且增加了网格划分的灵活性。为了更方便有效地生成多边形单元网格,在Delaunay三角形的基础上,通过将共圆Delaunay三角形合并为一个圆内接多边形,首先提出了Delaunay多边形的概念,进而提出了一种多边形网格自动生成的Delaunay多边形化算法。利用该Delaunay多边形化技术,对工程中常见的几何形状进行网格划分的具体算例表明,Delaunay多边形化方法可以生成性质优良的多边形单元网格。 相似文献
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P. Sampl 《Engineering with Computers》2001,17(3):234-248
An algorithm for the construction of the medial axis of a three-dimensional body given by a triangulation of its bounding
surface is described. The indirect construction is based on the Delaunay-triangulation of a set of sample points on the bounding
surface. The point set is refined automatically so as to capture the correct topology of the medial axis. The computed medial
axis (or better medial surface) is then used for hex-dominant mesh generation. Quad-dominant meshes are generated on the medial
subfaces first and extruded to the boundary of the body at both sides. The resulting single cell layer is subdivided in direction
normal to the boundary, yielding columns of hexahedral and three-sided prismatic cells. The resulting volume mesh is orthogonal
at the boundary and ‘semi-structured’ between boundary and medial surface. Mixed cell types (tets, pyramids, degenerate hexahedra)
may result along the medial surface. An advancing front algorithm (paving) is used for meshing the subfaces of the medial
surface. Development of the mesh generator has not been fully completed with respect to degenerate parts of the medial axis.
First medium-complexity bodies have been meshed, however, showing moderate meshing times. 相似文献
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二维任意域内点集的Delaunay三角划分的研究 总被引:38,自引:2,他引:38
传统的Delaunay三角划分不适合许多实际的应用,本文提出了三维任意域内点集的Delaunay三角划的概念,研究了其存储性、唯一性的条件以及一个三角划分是DTAD的充要条件,DTAD具有最小角最大以及平均形态比最大的性质,因此它是给定区域和点集的最佳三角划分,本文同时阐述了它的对偶图。 相似文献