数值方法

Numerical simulation method is an available method to analyze complex flow field.

计算结果表明，数值模拟方法是分析复杂区域流场的有效方法。

Based on the integrated compressible fluid mechanics equations,using eigen value analysis,the new method of non-reflecting boundary condition was proposed for aeroacoustics simulation of disturbance in shear flows.

基于完整的可压缩流体力学方程，利用特征分析的方法给出了气动声学中数值计算扰动的边界处理方法。

The computative methods and relative parameters are studied.

进而研究了数值计算方法和有关要素的确定方法。

By talking above problems, the paper brings forward a new concept that is called the background information of grid creation, and thinks over three points of the improvement of front advance, and puts forward and talks the essential of judging whether the polygon is concave or protruding and six practical methods.

在探讨过程中，本文提出了背景信息这一概念，考虑了改进阵面推进法的三个要点，提出并详细讨论了判断多边形凹凸方法的实质和六种实用方法，此外还着重对网格粗细会对数值计算产生什么影响及如何产生影响作了较严格的分析。

This semi-analytical method is more accurate then the numerical methods. And it overcome the disadvantage of analysis methods such as conformal mapping, the position of cracks can be random.

此方法属于一种半解析半数值的方法，由于充分利用了解析的结果，因而具有比较高的精度，同时又克服了保角变换等解析法的局限，各裂纹位置可以是任意的。

On the basis of Navier-Stoks equation and continuity equation, the SOLA-VOF method was adapted to calculate the field of velocity and pressure in fluid in this program. According to the inertia and continuity of fluid, a new velocity boundary conditions of free surface for 3dimensional fluid flow simulation had been developed. By the new method, any velocity condition occupied on the free surface of the fliud flow could be treated reasonably.

以流体的动量守恒方程和连续性方程为基础，采用SOLA-VOF方法，结合首次提出的流体惯性原理与连续性原理相结合的自由表面速度边界条件处理方法，研制出了流场数值模拟程序。

The application of the lattice Boltzmann method in unsteady open channel flows was studied in detail in the paper. An existing lattice BGK model was mended; For the problem of negative local equilibrium and evolutionary distribution, we proposed a lattice Boltzmann model based on cell-population equilibrium, which is a direct non-negative approximation to the continuous Maxwell distribution. The model reduces the transport and collision, two basic evolution steps in the LB model, to transport of the non-equilibrium distribution.

本文系统的研究了格子Boltzmann 方法在明渠非恒定流中的应用问题，改进了一个现有的LB 模型，数值实验表明此改进是有效的；在平衡态分布函数及分布函数的非负性问题上，作者提出了一个基于单元均衡的格子Boltzmann 模型，通过直接对Maxwell 分布函数的离散化实现对速度分布函数的非负离散，这种方法将传统模型演化过程中的碰撞和输运两个步骤直接表现为粒子的输运。

The discrete element method and the finite element method have their own advantages and weaknesses. Basically, the DEM was developed for predicting the failure problems accompanying with the transition from continuum to non-continuum media. However, it is not accurate to calculate the problem of continuum media. The FEM may forecast the failure area of the material reasonably, while it is hard to calculate the failure process in brittle media. Therefore it becomes a good choice to combine the two methods to construct a hybrid model.

离散元法和有限元法等数值计算方法各有其优势，同时也都存在不足之处：离散元法适于处理由连续介质向非连续介质转化的破坏问题，但对于连续体计算结果精度不高；有限元法适于预测材料破坏的区域，但难以直接用于计算脆性材料破坏过程，因此将两种方法结合可以形成一种较好的混合模型。

The approximate analytical solution may be expressed in terms of a rapid convergent power series with elegantly computable terms.

近似解结果和数值结果非常符合，证明了所提出的方法的准确性和可靠性，该方法可以用于解决其他科学和工程技术问题。

The numerical analysis method is used to study the ground movement laws caused by the ovalization variation in the cross section in the action of water and soil pressure of tunnel lining.Based on the stochastic medium theory,this paper suggests the method for calculating this ground movement caused by tunnel ovalization deformation.

采用数值分析方法研究了隧道衬砌在土水压力的作用下，断面所产生的椭圆化变形引起的地层位移规律，并基于随机介质理论，给出了计算隧道椭圆化变形引起地层位移的方法。

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。