共查询到17条相似文献,搜索用时 62 毫秒
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基于非结构四边形网格发展求解双曲守恒律的三阶加权基本无振荡(WENO)格式.针对任意非结构四边形网格选取重构模板,并给出基于线性多项式的三阶线性重构.但对于一般的非结构四边形网格,会出现非常大的线性权和负权,使得非线性重构的WENO格式对光滑问题也不稳定.本文给出一个处理非常大的线性权的优化重构方法,对优化后得到的负线性权采用分裂方法进行处理.对于非线性权,提出一种考虑局部网格和物理量间断的新光滑度量因子.采用优化重构方法和新的非线性权,当前的三阶WENO格式在质量很差的网格上也具有很好的稳定性.理论的三阶精度在数值精度测试算例中得到验证,同时一范数和无穷范数的误差绝对值不依赖于网格质量;具有强间断的数值结果证明了当前格式的有效性. 相似文献
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非结构网格生成Bowyer—Watson方法的改进 总被引:2,自引:0,他引:2
完善了应用Delannay原理生成非结构网格的Bowyer-Watson方法。通过求解简化Poission方程,灵活地控制网格的疏密,通过网格层次的区分,提高了网络的贴体性能;并通过分区,实现了适用于粘流计算的网格生成。 相似文献
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在数值模拟中, 非结构网格的优势是可以采用相同的数值格式统一处理任意复杂的计算区域, 但在网格生成过程中难度大, 并且不容易控制网格质量。树结构网格可以认为是介于结构网格和非结构网格之间的一种网格, 目前已经有相对成熟的方法快速在复杂区域内生成二维四叉树网格和三维八叉树网格。在实际应用中, 数值方法往往需要在连接协调的非结构网格上做离散, 树结构网格中不同尺寸的网格之间连接不是协调的, 在应用上会受到很多限制。文章实现了树结构网格到非结构混合网格的转换, 这种转换在二维情况下就是将四叉树网格转换为非结构三角形和四边形的混合网格, 三维情况下则将八叉树网格转换为非结构混合网格。这一转换过程的难点在于需要考虑数千种不同的八叉树单元, 并给出能实现连接协调的非结构混合网格划分。可以出现的网格单元包括六面体、三棱柱、金字塔和四面体这4种不同情况。通过特别的分类, 实现了程序的自动生成, 这种程序自动生成技术一方面可以避免人工编写大量程序时的失误, 另一方面也使得对数以千计的不同情况的处理成为可能。通过对几个简单网格的测试, 对网格数据转换方法做了初步的验证。 相似文献
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假设爆轰波阵面的法向速度是曲率的线性函数,在非结构四边形网格上采用水平集方法模拟爆轰波阵面的运动过程.水平集方程的曲率无关项采用正格式离散,曲率项采用伽辽金等参有限元方法空间离散,时间离散采用半隐格式.在笛卡儿网格和随机网格上,含曲率的水平集方程的离散格式为强一阶精度,重新初始化方程的离散格式精度为近似一阶精度.曲率收缩的不光滑界面和多个爆轰波阵面相互作用的算例说明格式可有效地模拟爆轰波与曲率相关的运动. 相似文献
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三维非结构网格自动生成 总被引:4,自引:0,他引:4
采用各向异性平面非结构网格生成技术对曲面的参数平面进行三角剖分,从而得到曲面的非结构网格,作为三维非结构网格的边界网格.应用推进面法生成网格内点,增量法将生成的内点逐点插入现有网格进行网格细化,得到三维计算域的Delaunay非结构网格.讨论了非结构网格质量优化方法.给出几个算例说明方法的应用. 相似文献
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二维非结构网格生成及Euler方程计算的方法研究 总被引:2,自引:0,他引:2
用离翼型表面最小作为阵面推进法中的参数选择依据。生成二维问题的非结构网格。这种方法戏了传统的背景网格观念,直接提供网格生成过程中所需的背景信息。在求解Eluer方程时,用格心格式的有限体积法作空间离散,用四步Runge-Kutta作时间推进,采用不同的加速收敛措施获得定常流动。提出了两这界条件的构造办法,并 不同边界条件对结果的影响。 相似文献
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非结构网格的并行生成 总被引:1,自引:0,他引:1
研究了非结构网格的并行生成方法.改进了R.Lohner的"波阵面"区域分裂算法以使子网格及其边界更有益于网格并行生成,提出了边界并行优化策略,改善了边界的光滑性;完善了子区域内生成网格时接受新点及新单元的条件,在界面网格生成过程中提出只接受新单元而拒绝新点的策略,节省了机时. 相似文献
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介绍一种可对任意二维区域进行非结构网格划分的方法,提出关于网格调整光滑的新思想,可对Laplace型滤波算子赋予新的意义。在此基础上再有目的选择松弛因子的大小,可达到同样的光滑效果而迭代次数显著减少。利用文献[3]提供的自动加点算法,对该方法稍加改进,就能完成自适应过程。利用该方法编制的程序,只需提供边界点座标,就能快速地得到满意的网格。 相似文献
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E. D. Dendy N. T. Padial-Collins W. B. VanderHeyden 《Journal of computational physics》2002,180(2):559
We present a new general-purpose advection scheme for unstructured meshes based on the use of a variation of the interface-tracking flux formulation recently put forward by O. Ubbink and R. I. Issa (J. Comput. Phys.153, 26 (1999)), in combination with an extended version of the flux-limited advection scheme of J. Thuburn (J. Comput. Phys.123, 74 (1996)), for continuous fields. Thus, along with a high-order mode for continuous fields, the new scheme presented here includes optional integrated interface-tracking modes for discontinuous fields. In all modes, the method is conservative, monotonic, and compatible. It is also highly shape preserving. The scheme works on unstructured meshes composed of any kind of connectivity element, including triangular and quadrilateral elements in two dimensions and tetrahedral and hexahedral elements in three dimensions. The scheme is finite-volume based and is applicable to control-volume finite-element and edge-based node-centered computations. An explicit–implicit extension to the continuous-field scheme is provided only to allow for computations in which the local Courant number exceeds unity. The transition from the explicit mode to the implicit mode is performed locally and in a continuous fashion, providing a smooth hybrid explicit–implicit calculation. Results for a variety of test problems utilizing the continuous and discontinuous advection schemes are presented. 相似文献
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We propose a novel scheme to probabilistically teleport an unknown two-level quantum state when the information of the partially entangled state is only available for the sender. This is in contrast with the fact that the receiver must know the non-maximally entangled state in previous typical schemes for the teleportation. Additionally, we illustrate two potential applications of the novel scheme for probabilistic teleportation from a sender to a receiver with the help of an assistant, who plays distinct roles under different communication conditions, and our results show that the novel proposal could enlarge the applied range of probabilistic teleportation. 相似文献
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We propose a novel scheme to probabilistically teleport an unknown two-level quantum state when the information of the partially entangled state is only available for the sender. This is in contrast with the fact that the receiver must know the non-maximally entangled state in previous typical schemes for the teleportation. Additionally, we illustrate two potential applications of the novel scheme for probabilistic teleportation from a sender to a receiver with the help of an assistant, who plays distinct roles under different communication conditions, and our results show that the novel proposal could enlarge the applied range of probabilistic teleportation. 相似文献
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A new kind of k-quantum nonlinear coherent states, i.e., the k eigenstates of the
k-th power $\hat{B}^{k}$ (k≥3) of the
generalized annihilation operator $\hat{B}=\hat{a}\frac1{f(\hat{N})}$
of f-oscillators, are obtained and their properties are discussed.
The completeness of the k states is investigated. An alternative
method to construct them is proposed. It is shown that these states
may form a complete Hilbert space, and all of them can be generated by
a linear superposition of k Roy-type nonlinear coherent states.
Physically, they can be generated by a linear superposition of the
time-dependent Roy-type nonlinear coherent states at different
instants. 相似文献