查询词典 numerical computation

The computation of matrix exponential which ties up structural mechanics and optimum control is one of the extensive topics in numerical mathematics.

矩阵指数计算与力学计算中的动力学问题、最优控制的计算问题等密切相关，是数值代数里研究得最为广泛的课题之一。

By numerical simulations of occultation eve: its, it is proved that the new method not only has a simple mathematical expression and the minimum computer time consuming, but also a lower computation error.

它的研究成果将在国民经济、大气科学研究和高新武器的发展中起重要的作用。从而成为当前空间探测技术的研究热点之一。

Scanning each character in the expression to separate and record operators, operational symbols and data types of operators, when expression being correct in syntax, recording interpreter executive order based on precedence of operator, a general expression interpreter is designed. The interpreter not only is used for numerical value and string computation, but also is easy to extend its functions, and when batch converting data, it could catch run error and continue to successive data.

2通过对公式的一次扫描，记录操作数、操作符号和操作数的赋值特性，并在语法正确的情况下，记录公式基于算符优先级的解释执行顺序，设计了通用公式解释器，它不仅可以进行数值运算、字符运算，而且可以对使用的函数库方便地进行扩充，在批量进行数据转换时，可以记录运行时错误，而不影响后续数据的执行。

On the basic of above job a mathematical model of simulation turbulent flow with free surface is established and triumphantly applied to numerical computation on 2D spillway and 3D spillway with frusta of brake.The material job and main conclusion are as follows:(1)A simple boundary orthogonalization procedure independence grids generation method is put forward on the base of algebraic grid generation method; Data structure and computational model on interface are established aiming at blocks of structured grids.

本文针对粘流场数值模拟技术的研究现状和发展动态作了比较全面的回顾与展望，重点研究了网格生成技术、数值求解技术、湍流模型技术和动边界模拟技术，在此基础上建立了模拟自由面湍流场的数学模型，并成功地应用到二维溢流坝和带闸墩的三维溢流坝过坝水流的数值计算。

So a method that combining the model experiment and numerical computation are discussed in this paper. The flow-induced vibration response of the plane recumbent gate in ShangHai qingshui river is computed in this method, and the result is reasonable and credibility, this method can be extend to compute the other hydraulic structures like overfall dam, guide wall, gate pier and so on, which is under fluctuating pressure.

由此探讨了一种将水力模型试验跟数值计算相结合来计算闸门流激响应具体值的方法，并应用于上海清水河泵闸水下卧倒门的流激响应计算上，结果合理可靠，该方法可以推广应用于溢流坝面、导墙、闸墩等受水流脉动荷载作用的其它水工建筑物。

In this paper, a numerical computation of pressure on overline bridge surface by a high- speed train head is carried out with 3D Panel method.

采用 三维不可压缩势流模型和面元法，对高速列车通过时作用在跨线天桥表面上的气动压力进行了数值计算。

Therefore,it is necessary to research diffusion equation for suspended sediment because it describes the sediment move process in the water body.The equation is a various coefficients second-order linear partial differential equa-tion,such equation under complex boundary condition is very difficult to get its analytical solution,while its numerical solution relative analytical solution is more easier and has the obvious superiority:simple,the computation convenience.but to get a kind of difference format which is good accuracy and stability is not easy.

泥沙扩散方程实际上是一个变系数的二阶线性偏微分方程，这样的方程在各种复杂边界条件下求解是十分困难的，求它的解析解在数学上存在着难以克服的障碍，无法求出其精确解，因此常用数值方法求它的近似解，相比较而言，数值方法有着明显的优势：即简单灵活、计算方便快捷，但要寻找一种精度高、稳定性好、计算方便的差分格式也并非易事。

Based on potential flow assumption, numerical model of bubble dynamics is erected and corresponding computation program is exploited.

基于势流假设，建立气泡动力学数值模型，并开发计算程序。

The advantages and limitations of every kind of methods for calculating the failure probability is reviewed. The frist order reliability method, the second order reliability method and many kinds of boundary method have achieved remarkable success and formed nature fields of reliability. However, the precision of these methods decrease as the increase of complexity of problem. The numrical methods are versatile, except numerical intergration is only adaptable to special problems which have small number variables and regular intergral domain. Particularly, the advanced variance reduction techniques own the following character: high precision and a small amount computation. But some questions remain to study in the future because only an initial work about these techniqes is developed.

全面评述了计算失效概率各种方法的优点和局限性，其中经典的解析法包括一次可靠性方法、二次可靠性方法、一阶边界法、Vanmarcke上边界、PENT上边界和Ditlevsen二阶窄边界法，这些方法对于多设计点、变量较多且相关、密度函数不是正态以及极限状态方程较复杂的情况，其计算精度较差；而已有的数值方法却是具有较好的通用性，其中除数值积分法只对变量较少、积分域较规则的特殊问题适用外，各种数值模拟方法均具有较广的适应性，特别是各种改进的方差减小技术，精度高、计算量小，但由于其处在研究的初级阶段，还有许多问题有待于解决。

Ritz variation method was used to find the numerical relation between the energy near the ground-state of the hydrogen molecular ion H 2 + and the changes of the variation parameter and the bond length,the computation formula of bond length and ground-state energy for H 2 + was also obtained by means of the method of parabolic interpolation .

用Ritz变分法求出了氢分子离子H2 +基态能量附近的能量随变分参数和分子键长变化的数值关系，并用抛物线插值法获得了H2 +键长和基态能量的值及其计算公式，比文献 [1，2 ]更接近于实验值。

There are different types of personal loans available.

有许多不同类型的个人贷款优惠。

The above mentioned teaching model of spiral rising can be used to avoid rigidness in teaching.

上述螺旋式上升的教学模式，可以避免教学形成模式後的僵化现象。