数值

This thesis contributed to the comprehensive study of the Finite-Difference Time-Domain method and its application to the numerical computation of radiated electromagnetic fields in switched mode power supplies. The work includes mainly three parts: the study on the performance of PML absorbing boundary condition applied to pseudo low frequency electromagnetic problems; the validation of the FDTD method with PML absorbing boundary conditions and the corresponding computer software based on the numerical study of the electromagnetic field of an electric dipole antenna, and its application to the numerical computation of radiated electromagnetic fields in switched mode power supplies; the development of an improved alternating direction implicit finite-difference time-domain method.

在综合前人工作基础上，本文对时域有限差分法及其在开关电源辐射电磁场数值计算中的应用进行了系统的分析和研究，其核心内容包括：伪低频电磁场数值计算中PML吸收边界条件性能的研究；基于基准问题—电偶极子天线三维辐射电磁场，验证了本文构造的基于PML吸收边界条件的三维FDTD法及其计算软件，并应用于高频开关电源辐射电磁场的数值分析；提出了一种改进的交替方向隐格式时域有限差分法。

The unique advantage of this halfanalytical numerical method is that the analytical process of Conformal Mapping can transform an irregular area into a regular one such as a rectangle. Therefore, the discretization error of numerical methods on the boundary can be avoided, and the numerical algorithm can be implemented more easily, with the computing efficiency improved.

这种保角变换的半解析数值方法的突出优点是：利用前期的保角变换解析处理将不规则的场域转化为规则的矩形域，从而避免了纯数值技术对复杂边界的离散化误差，降低了后期数值计算的算法复杂度，并提高了计算效率。

The experimental setup for the turbulent jets in crossflow is designed, and the hot wire anemometry IFA 300 is used to measure the velocity field and the turbulent kinetic energy, and the computational result matches experimental measurement reasonably well. The experimental result is very important in the analysis of the flow field, deduction of the equation of the jet trajectory, check of the turbulence model and validation of the numerical method.

首先，建立了用于测量横向紊动射流的实验台，并利用IFA 300型热膜风速仪系统测量了多种工况下的流场，并将速度、湍动能结果与数值计算结果进行了比较，实验结果与数值模拟结果吻合较好，从而为分析流场特性、确定射流轨迹、比较湍流模型以及验证数值计算方法提供了依据。

In Chapter 2, one kind of rational cubic spline interpolation with linear denominator has been proposed, whose derivatives are replaced with accurate derivative values, difference quotient and arithmetic average difference quotientrespectively.

第二章给出了一类分母为线性的有理三次插值函数，当其导数值分别取为导数的精确值，一阶差商，以及算术均差商时，便得到三种插值格式，分别为给定导数值的有理三次插值函数，基于函数值的有理三次插值函数，以及基于算数均差商的有理三次插值函数。

Took Chongqing Gong-he tunnel as an engineering example and studied the failure mechanism of surrounding rock and the correlation with bolt support system by using the methods of theoretical analysis, modeling test, numerical simulation and in situ test, some helpful conclusions were arrived as follows.Firstly, a new failure criterion for transversely isotropic rock mass was proposed with consideration of bedding plane orientation and major principal stress, and the corresponding algorithm, arrived through VC++6.0, can be easily embedded into the software FLAC3D for the geotechnical calculation.

论文在国家自然科学基金专项基金创新群体基金项目(No.50621403)以及国家自然科学基金重点项目"隧道与地下空间工程结构物的稳定性与可靠性(No.50334060)"的资助下，以共和隧道为示范工程，运用理论分析、物理模型实验、数值模拟和现场测试等手段，对共和隧道大埋深段层状岩体的围岩变形破坏机理、锚杆支护力学效应及围岩-支护结构的变形特征等内容进行了研究，其主要研究成果有：①在总结和探讨国内外学者提出的层状岩体经验型连续介质破坏准则基础上，结合层状岩体力学特性，考虑层面方向和最大主应力方向两个影响因素，提出了共和隧道层状岩体横观各向同性破坏准则；采用汇编语言VC++6.0实现了横观各向同性弹塑性本构关系的算法，并嵌入FLAC3D有限差分数值分析软件接口中实现数值运算。

It shows that a remarkable advantage of the symplectic methods applied to the Schrodinger equation is the precise preservation of charge conservation law. In order to study the numerical stability, we also adopt the different time step sizes.

为了比较，我们还给出了同阶的非辛算法的数值模拟，从而得到辛摄动配置算法和其在理论上等价的辛龙格-库塔方法在数值上的等效性以及辛算法在数值计算中的优越性。

By using the meshless method, a numerical ocean engineering basin was established to simulate irregular waves propagated in shallow water. Locating the source points outside the computational domain, the problem of water wave propagation was solved by collocation of only a few boundary points instead of meshes.

采用基于配点和径向基函数的无网格数值模拟方法，建立数值海洋工程水池，将源点布置在模拟波浪场之外，沿边界布置配点而不是划分网格；对深水不规则波经斜坡过渡后在均匀水深浅水域中传播的过程进行无网格数值模拟和波谱的迭代修正。

We introduce the notion of fuzzy-valued continuous function on a compact set K in a metric space, and discuss its properties; On this base, we study the uniformly d∞-convergence of a sequence of fuzzy-valued continuous function on K. We prove that the space of fuzzy-valued continuous functions on K, i.e. C(K, E1), is a complete metric space with respect to the metric D.

引入了定义在某度量空间的紧子集K上的模糊数值连续函数和水平连续函数的概念，讨论了它们的某些性质；在此基础上，研究了K上模糊数值连续函数列的一致d∞-收敛性，证明了K上模糊数值连续函数空间C(K， E1)关于度量 D 构成一个完备的度量空间。

A new method for the generation of curvilinear grid has been proposed. Some curvilinear grid generation examples show that satisfactory grids can be generated for simple-connected regions and connected- regions with complex boundary by using the proposed adjusting factors.

3提出了一种生成边界处正交曲线网格的新方法，收敛速度快，在复杂边界流场区域的数值计算中，有很大的实用价值；为了克服复杂几何边界给数值计算带来的困难，提高通用性以及水流的预测精度，本文采用上述网格生成技术，在直角坐标系三维非恒定明渠紊流的沿层积分数值模型基础上，发展了曲线坐标系下的多层紊流水动力模型。

This paper used commerce software FLUENTS to implement numerical simulated compute because it could in more detail and comprehensive open out the distribution laws of the flow field in the channel and in the holes and the experimental results had been consummately enlarged. At last, the experimental results were contrasted and analyzed with the computational ones.

本文还利用商业软件FLUENT5进行了数值模拟计算，数值计算可以更详细更全面地展现通道内以及孔内流场的分布规律，更加丰富和完善了实验测量结果，并将实验结果和数值计算结果进行了对比分析。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。