查询词典 numerical algorithm

At first, the velocity which is the outlet velocity of 2-D numerical model by using the VOF and κ~εmodel is used as the inlet velocity of the 3-D numerical model. The control equations of 3-D water and sediment movement are described in the orthogonal curvilinear coordinates, and the equations is segregated by using the Finite Volume Method.

以二维的水气两相流的VOF 模型结合雷诺时均法的κ~ε双方程模型进行水气两相流计算，得到稳定流场作为三维水沙计算的初始进口条件。

Keywords: Delay differential equation;Numerical method;Numerical stability

中文关键词：延时微分方程；数值方法；数值稳定性

This paper studies the main geometrical parameter such as angle, height, width, stagger and the upper width in dentation and trapezoid flow path, firstly, uses the single-phase numerical simulation of the computational fluid dynamics technique to analyse the influence of different geometrical parameter on discharge coefficient and flow state exponent of drip emitter. Secondly, uses the two-phases numerical simulation of CFD (1% sand content ) to analyse the influence of the above mentioned geometrical parameter on the contribution regulation of sand and anti-clogging performance. Thirdly, uses the PIV （ particle Tracking Velocimetry ） technique which can see the small-scale flow path to observe and test the trajectories and velocities of solid particles in labyrinth flow path, and analyses the basic factors which can influence the movement characteristic of solid particles and the flow state in flow path.

本文以齿形流道、梯形流道为主要研究对象，以流道转角、流道高，流道宽、偏差量及梯形流道上底宽为主要结构参数，首先应用 CFD 单相流数值模拟技术对不同结构参数灌水器流道水力性能进行模拟，分析了不同结构参数对流态指数和流量系数的影响，其次，应用 CFD 两相流（含沙量为1%）数值模拟技术分析了结构参数对含沙量分布规律和抗堵塞性能的影响，然后，应用 PIV 可视化测试方法测试了固体颗粒在流道内运行轨迹及速度，分析了影响固体颗粒运动特性及流道内流体流态的基本因素，最后，对上述流道结构形式通过模具加工及滴灌带试制，进行了标准化测试（ GB/T 17187-1997 农业灌溉设备滴头技术规范和试验方法与 ISO 标准 ISO /TC23 /SC18 /WG5N4短周期堵塞测试程序），测试结果验证了 CFD 模拟结果，并提出了迷宫结构流道灌水器的抗堵塞设计方法。

In order to analyze the influence of the center air pipe diameter change on the combustion effect, numerical modeling was applied to numerical calculation on the temperature field of such type of boiler,through which temperature field in five different schemes were obtained. In addition, the influence law of change of the diameter of the center air pipe on the temperature field was analyzed. The temperature of the nearly-back wall region takes on a firstly decreasing and then increasing change with the diametrical decrease of the central wind pipe.

为研究改变中心风管直径后的4层燃烧器对炉膛燃烧的影响，采用数值模拟的方法对该型锅炉炉内的温度场进行数值计算，得到5种不同方案下该型锅炉炉内的温度场分布，并分析了中心风管直径的改变对炉内温度场的影响规律，即后墙近壁区温度随着中心风管直径的减小呈现先降低后升高的趋势。

In most situations, the polysome system dynamic equation is the non-linearity the ordinary differential equation or the differential - algebra system of equations, it is generally obtains the equation through the computer value simulation then get the numerical solution, then through to numerical solution analysis, understanding polysome system dynamics characteristic.

多数情况下，多体系统的动力学方程是非线性常微分方程或微分-代数方程组，一般是通过计算机数值仿真得到方程的数值解，然后通过对数值解的分析，了解多体系统的动力学特性。

Application of FLAC and numerical differential to surface deformation observation;2. The formulas solving numerical differential and integral of discrete function arc deduced in this paper.

推导了三次样条插值在求解列表函数的数值微分与积分的公式，给出了余项估计，编写了用于求解数值微分与积分的通用程序，通过数值算例表明，三次样条在插值逼近中具有非常好的性质。

Traditionally, the numerical simulation studies of gas-solid turbulence flow are based on Reynolds-Averaged models which are not able to get accurate results. While with the rapid development of computer science, direct numerical simulation method becomes more and more vital hotpoint.

传统的研究气固两相湍流数值模拟是基于平均的思想，其无法描述流动的精确结构等缺点让直接数值模拟的方法在这个方面随着高性能计算机的出现而飞速发展。

The finite element method and direct numerical integration method are used in the calculation. Through an engineering example, the numerical simulations of time-course response and axes contrail are respectively carried out when the units are acted under transient initial displacements and transient imbalance loads.

采取有限单元法和直接数值积分法相结合的方法，结合工程实例，对机组在瞬时初位移和瞬时不平衡载荷作用下的时程响应及轴心轨迹分别进行了计算机仿真计算，并对计算结果进行了分析和讨论。

In this dissertation, research work of near-field numerical simulation is briefly reviewed, some existing problems are analyzed, and the following problems in decoupling numerical simulation, which is a key research direction in present, are studied.

本文简要地回顾了近场波动数值模拟的研究工作，分析了存在的问题，并针对当前的一个主要发展方向—数值模拟的解耦技术，对下列问题进行了研究。

In this dissertation, the author discusses the numerical solution for the direct acoustic scattering problem with the Neumann boundary condition, and pays more attentions to discuss numerical recovering the shape of the obstacle region, which is the inverse problem of the direct acoustic scattering problem with the Dirichlet or impedance boundary condition.

本文重点研究了Neumann边界条价下的声波障碍散射正问题和Dirichlet、Impedance边界条件下的声波障碍散射区域反问题的数值计算方法，得到很好的理论结果和数值结果。

Many will continue to choose to live in duality and in conflict.

许多人将继续选择活在二元对立性和冲突中。

I find that students of the University of Physical Education all wear sportswear at first sight.

我发现：体育大学的学生乍一看，都是穿运动衣，大家都一样