数值方程

Then, the turbulent SRNS equations and the two equation k-ε turbulence model are presented in Cartesian coordinate system, the equation of turbulence model is parabolized to adopt the space marching method.

为了数值模拟湍流流动，给出了直角坐标系下湍流SRNS方程及K-ε双方程湍流模型，并对K-ε方程进行了流向抛物化以适应空间推进求解的要求。

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。

A numerical method, where the pressure is used as a primary dependent variable, is presented for the solution of the two-dimensional steady Navier-Stokes equation in general curvilinear coordinates. SIMPLE (Semi-Implicit Method for Pressure Linked Equations) is mainly adopted.

本文首先详细推导了二维任意曲线坐标系下张量形式的流动控制方程及其和压力修正方程的离散形式，应用求解压力速度耦合的SIMPLE算法，以压力为主要求解变量对Navier-Stokes方程进行数值求解。

Diophantine equation is an important subject in number theory.

凡是变数个数多于方程个数且取整数值的方程称为不定方程。

The forward kinematics is analyzed by choosing one of the mechanisms which have one, two,three or zero angle constraint.Wherein,3-CCC is a new parallel mechanism which has three angle constraints and three distance constraints, Calay\'s formular and direction cosine matrix are used to describe the rotation matrix respectively.By setting Dixon\'s and Sylvester\'s resultant with the three angle constraint equations respectively and using parameters replacement to deal with the distance constraint equations,the 64 order input-output equation of the forward kinematics is obtained under both of the methods.Numerical example confirms these theretical results and the motion simulation is shown in VC++ by integrating OpenGL.

3对高小山提出的广义并联机构进行了研究，以其中具有角度约束的并联机构进行了分析，选取具有一个、两个、三个和零个角度约束类型中各一个机构进行了运动学正解求解，其中3-CCC是一种全部由圆柱副构成的具有三个线线角度和三个距离约束的新型并联机构，文中分别用Calay公式和方向余弦两种旋转矩阵建模方法对其位置正解进行了分析，通过对三个角度约束方程分别构造Dixon结式和Sylvester结式，以及对三个距离约束方程进行变量代换分别导出了位置正解输入输(来源：4040ABC论文网www.abclunwen.com)出方程，得出64组位置正解，并使用数值算例验证了其全部根。

Initial boundary value problem of two dimensional unsteady diffusion equations is solved in this paper. By using time-dependent fundamental solution of two dimensional diffusion equations and the extension of double layer potential, we establish virtual boundary integral expression of diffusion equations. Then virtual boundary element method is used to implement the numerical computation.

本文在求解二维非定常扩散方程的初边值问题时，利用二维扩散方程与时间有关的基本解，基于双层位势的延拓，建立二维扩散方程的虚边界积分表达式，然后利用虚边界元法进行数值计算。

Under the assumption that the Earth is a triaxial rigid body which is rotating freely in the Euclidian space, the elliptic integral solution of the Euler dynamic equation is provided, and then the numerical solutions of the Euler dynamic as well as kinetic equation are realized.

在Euclid空间中，假定地球是一个作自由旋转的3个主惯性矩互不相等的刚体，给出了Euler动力学方程的椭圆积分解，并实现了Euler动力学方程和运动学方程的数值解。

To be a contrast, Euler equations were solved in the same condition, and the numerical experiments demonstrated that for such strongly unsteady flows with a high Reynold number, the Euler solution is comparable to the N-S solution.

在同样计算条件下采用Euler方程进行对比性研究，数值实验发现对这类大雷诺数、强非定常性的问题，Euler方程和N-S方程得到的结果相差不大。

Based on the Biot s two-phase theory for fluid-saturated porous media, considering the inertia force of the solid and the liquid, and the coupling function between the solid and the liquid, and the compressibility of the liquid in allusion to the character of the nearly saturated soils. The dynamic governing differential equations are solved by Hankel transform. Then, considering the boundary condition, the dual integral equations of vertical vibration are established which are reduced to Fredholm integral equation of the second kind.

本文基于Biot两相介质动力固结理论，针对准饱和土地基的特点，考虑了流体的可压缩性，土体和流体的惯性及水土之间的耦合作用，运用Hankel变换技术求解动力控制方程，然后按混合边值条件建立起对偶积分方程，并将其化为易于数值计算的第二类Fredholm积分方程，分别研究了准饱和土半空间地基、上覆单相弹性层的准饱和土地基和准饱和粘弹性地基上刚性基础的竖向振动特性。

The functional by variational calculus leads to a set of elliptic partial differential equations,in particular,Poisson equations,which is possibly solved by numerical methods.

利用变分法可以从这个二次误差指标函数导出一组椭圆形偏微分方程泊松方程，这类方程有相当成熟的数值解法。

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。