数值方法

Based on the Volume of Fluid Method, the wave damping absorber of the numerical wave flume for irregular waves has been investigated. Setting the Turbulence motion equation and the Renault equation as the governing equations and using the wall function technique in the near-wall region, an absorbing wave-maker is set at the left side of the flume.

本文对基于VOF方法的不规则波数值波浪水槽进行了阻尼消波研究，以湍流运动方程一雷诺方程为控制方程，在近壁区应用壁函数技术，在数值波浪水槽的左端设置了主动吸收式造波机。

A two-steps numerical method has been used to deal with this process. In every computation time-step, two phases are used: the first one is the adiabatic expansion and cracking phase; the second one is the phase of absorbing laser energy.

采用两步数值计算方法处理等离子体微滴的爆炸过程，即在每一个数值计算时间步长内，将爆炸过程分为两步，第一步处理微滴的绝热膨胀及裂解过程；第二步处理微滴对激光脉冲能量的吸收过程。

The main works include: In this thesis, we use Finite Difference Time Domain method to study the relationship between diffraction efficiency, angular dispersion and grating constant, to discuss how the grating figure influence the diffraction efficiency, and to research the frequency spectrum characteristic.

主要工作包括：本文分别在垂直入射和自准直入射（光垂直于光栅刻槽面入射）情况下，采用时域有限差分方法，利用商业数值计算软件OptiFDTD对二维闪耀光栅进行了矢量电磁场数值计算，研究了光栅的衍射效率和角色散随光栅常数的变化情况，研究了光栅形状对光栅衍射效率的影响，还讨论了各种光栅的频谱特性。

For the radiation transfer equation, both the spatial domain and the angular domain is discretized, and the finite volume method is used to solve the equation in an explicit way.

把一种新的三维热辐射计算方法应用到高超声速非平衡流场的数值模拟过程中：在非结构网格上对高超声速化学非平衡流场的数值模拟过程中，耦合了辐射输运方程来求解辐射热流。

Chapter 9: We report a large quantity of numerical experiments of 13 different algebraic multigrid algorithms for solving the Poisson equation, anisotropic equation, equation with cross-derivative terms, general matrix problems with large off-diagonal positive entries, biharmonic equation, Toeplity matrix, elasticity systems, finite element discretization of the Laplacian and even 3D problems. Particular attention is focused on asymptotic convergence factors and CPU-time consumed. Numerical results for many different types of practical problems demonstrate the efficiency and robustness of the proposed algebraic multigrid methods.

第九章：在各种代数多重网格算法的基础上，进行了大量的数值试验，具体给出了十三种不同的代数多重网格方法求解泊松方程，各向异性方程，带混合导数项的方程，带有大的非对角正元素的一般矩阵问题，重调和方程，托普利兹矩阵，弹性力学方程组，拉普拉斯算子的有限元离散，甚至三维问题的较为丰富的数值结果，重点关注它们的渐近收敛因子和所需的CPU时间，来源于不同类型问题的计算结果既为代数多重网格理论分析和算法的改进提供了很实用的资料，同时也证实了本文给出的代数多重网格算法的效绩和稳健性。

Initial random imperfections of composite panels are assumed to be Gaussian random fields and simulated numerically from their mean and autocovariance functions. Lindstedt-Poincare's perturbation technique is employed to solve the resulting nonlinear equation in the vibration analysis of imperfect composite panels. Monte Carlo analyses are performed for detailed numerical calculations.

层板之随机性几何缺陷以高斯随机场来描述，并利用其平均值函数及自方差函数来做数值的模拟；以Lindstedt-Poincare微扰方法来处理缺陷复合层板之非线性运动方程式，并使用蒙地卡罗法来做详细的数值分析。

The determination of Avogadro Constant many ways, using oil-drop experiment, electrolysis, X-ray diffraction of different options, the measured values are different, 602 × F1023 mole -1 is only an approximation.

实验测得其数值约为602×F1023。阿佛伽德罗常数的测定方法很多，采用油滴实验、电解法、X射线衍射等不同方案，测得的数值不尽相同，602×F1023摩尔－1只是近似值。

This dissertation has combined model experiment and numerical simulation and detailedly analyzed the SPRT and hydraulic grade line method for leak detection. This method is superior to others on low expense and simple maintenance. It is practical for actual projects

本文综合运用了模型试验和数值计算的方法对输液管道泄漏监测方法进行了较全面的分析，得到了瞬态识别和稳态定位的监测方法，该方法简单易行并且造价低对长距离输液管道的泄漏监测非常实用。

Firstly, based on the sliding mode control and backstepping technique, a new attitude tracking controller is derived to control the attitude motion of spacecraft, the stability of the system is analyzed via Lyapunov method and the reaction wheel dynamics is also considered from the real applications point of view. The whole design process is divided into two steps: the first step is to use sliding control technique to design suppositional adaptive variable structure controller; and the second step is to design attitude tracking controller based on SMC and backstepping technique. Numerical simulations are performed to show that both tracking maneuver and vibration suppression can be accomplished effectively.

首先，采用自适应后步法结合主动振动控制技术设计了姿态跟踪鲁棒控制器，基于Lyapunov方法分析了系统的渐近稳定性；在此基础上，显性地考虑了执行机构动态特性问题，将整个设计过程分为两个步骤：第一步采用滑模控制技术设计了变结构虚拟控制器，给出自适应控制律的设计方法；第二步，将后步法与滑模控制技术相结合，设计了姿态跟踪鲁棒控制器，给出飞轮电压的输入算法及稳定性分析；最后，将提出的控制方法应用于挠性航天器的姿态跟踪控制，通过数值仿真对所提方法的可行性与有效性进行分析和验证。

In this paper, test research have been performed on the two important mechanical properties indicator compressive modulus of elasticity and shear modulus. Numerical simulation has been performed on the base of results of test under the situation uniform and uneven thickness of elastomer layer, which analyze internal stress distribution of the elastomeric bearing, as follows:(1) The traditional test methods of compressive modulus of elasticity test are rather cumbersome and take up experimentalists lots of time. This paper has improved the traditional test methods of compressive modulus of elasticity test, which has collected the holding-load time together to concentrate on holding load. The tests have been performed on different types of bearings, which results show that the results of the improved test method conform to the error range regulated by the standard and can effectively save time for the experimentalists, also eliminate the accumulative error.

本文主要对板式橡胶支座的抗压弹性模量、抗剪弹性模量两个重要力学性能指标进行试验研究，并在试验结果的基础上对均匀胶层厚度和不均匀胶层厚度两种情况进行数值模拟，分析橡胶支座内部应力分布规律，具体内容如下：(1)传统抗压弹性模量试验方法比较繁琐，占用试验人员大量时间，本文对传统抗压弹性模量试验方法进行了改进，将持荷时间集中起来进行集中持荷，通过对不同类型支座进行试验，试验结果表明该改进试验方法所得结果符合标准规定误差范围，为试验人员节省了大量时间，并且还消除了传统方法中的累计误差。

They weren't aggressive, but I yelled and threw a rock in their direction to get them off the trail and away from me, just in case.

他们没有侵略性，但我大喊，并在他们的方向扔石头让他们过的线索，远离我，以防万一。

In slot 2 in your bag put wrapping paper, quantity does not matter in this case.

在你的书包里槽2把包装纸、数量无关紧要。