数值方法

The characteristic approximation is used to handle the convection part along the direc-tion of fluid namely characteristic direction to ensure the high stability of the method in approximating the sharp fronts and reduce the numerical diffusion; The mixed finite element spatial approximation is employed to deal with diffusion part and approximate the scalar unknown and the adjoint vector function optimally and simultaneously; In order to preserve the integral conservation of the method, we introduce the modified characteristic method.

该方法对方程的对流部分沿流体流动的方向即特征方向离散以保证格式在流动的锋线前沿逼近的高稳定性，消除数值弥散现象；对方程的扩散部分采用最低次混合有限元方法离散、同时以高精度逼近未知函数及未知函数的梯度；为保证方法的整体守恒性，在格式中引入修正项。

And nonlinear finite element numerical simulation is one of the most effective methods among them.

其中，非线性有限元数值仿真方法是目前最为有效的方法之一，也是最符合实际的一种方法。

After analysing the existing smooth orientation interpolation methods we proposed a smooth orientaion interpolation method based on cubic cardinal spline in quaternion space. This method possesses the following advantages: interpolation, C〓 continuity, accurate evaluation of the quaternion value at arbitrary parameter, transparent to the users, adjustable parameters for controlling the velocity of orientation change.

在分析现有的朝向光滑插值方法基础上，提出了基于四元数空间三次C样条的朝向光滑插值方法，该方法具有插值、C〓连续、任一参数处的四元数值可精确求得、对用户透明、可以用参数调节关键帧处物体朝向变化的速度等优点。

Finite Element Method is an important means of engineering subject and has been proved to be a common method in many subjects. However, disadvantages still remained. During the structural analysis, large amount of high-order units were used in order to ensure the precision of arithmetic solution when using Finite Element Method to do discrete processing. This will cause high order of coefficient matrix of corresponding equation group.

有限元方法是工程学科的重要工具，被证明为在许多科学和工程领域中连续物理系统模拟的一种普遍方法，但缺点是随着工程结构分析问题越来越复杂，在结构分析中，为保证数值解的精度，在使用有限元方法离散处理时，往往要用大量的高阶单元将结构剖分得很密，这时相应的代数方程组的系数矩阵的阶数很高，即使用目前速度最快的串行机来进行求解，费时仍然太多且问题的规模受到内存容量的限制。

Using spherical harmonic function expansion and finite element method,Boltzmann transport equation is solved numerically,the convergence of the method is approved.

讨论了谱有限元方法在中子测井数值模拟中的应用，用球谐函数谱展开和有限元耦合方法求解Boltzmann中子输运方程，得到了这种耦合方法的收敛性。

A direct method is implemented for computing the free-term coefficient and the Cauchy principal value integral in the higher-order boundary element method for potential flow.

采用直接数值计算方法计算了势流问题高阶边界元方法中的自由项系数和柯西主值积分，建立了波浪与结构物作用的一种高阶边界元方法。

Then the boundary element integral equation of interior and exterior form is deduced in detail, also the form with corner coefficient. The significance for numerical calculation and principle of the singular integral is analyzed, and a non-isoparametric transformation method is presented to calculate weak singular integral and Cauchy integral, the method presented provides us a very simple way to computer the two kinds of singular integral of Helmholtz boundary integral equation, and it is easy to program in computer. After the difficulty of the calculation for multi-frequency of Helmholtz boundary element is explained, a method named SECHIEF (Series Expansion Combined Helmholtz Integral Equation Formulation), which is focused on the computational efficiency, is presented.

对结构声辐射的边界积分方程的内部形式与外部形式进行了详细的推导，给出了角点系数的计算方法与边界积分方程的形式，在此基础上，分析了奇异积分产生的原理及其对数值计算的重要性，提出了一种计算奇异积分的非等参(来源：Ae8a8BC论文网www.abclunwen.com)单元的变换方法，该方法给Helmholtz 声学边界积分方程中的弱奇异积分与Cauchy 奇异积分的计算以及编程提供了极大便利。

Aimed at characteristic of heavy oil reservoir, we choose CMG software for numetrial simulation.

本文应用测井解释方法与数值模拟方法结合的新方法来研究剩余油分布，取得了较好的效果。

The MUSCL method of Godunov schemes is developed to simulate the complex flow fields of two-dimensional (2-D) and...

本文首次采用Godunov类数值格式中的MUSCL方法对二维、三维复杂火箭导弹燃气射流冲击流场进行了比较全面系统的理论研究和数值仿真。

The MUSCL method of Godunov schemes is developed to simulate the complex flow fields of two-dimensional (2-D) and three-dimensional (3-D) flow field of rocket jet impingement in this paper.

本文首次采用Godunov类数值格式中的MUSCL方法对二维、三维复杂火箭导弹燃气射流冲击流场进行了比较全面系统的理论研究和数值仿真。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。