数值计算

The results of field test indicate that the earth pressure of abutment,different from lin...

有限元分析结果表明，台背土压力分布存在一定的空间效应，在同一深度上数值并不相等，中间大，两侧小。用库仑公式计算的结果比数值计算与实测的结果偏于安全。

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。

Some concepts about the reliability are described, and the method for calculating the reliability of system is provided by making linear substitution. While taking Stochastic Finite Element Method into the reliability calculation, a Nonlinear SFEM model is founded, and methods to resolve some problems in SFEM calculation are given. So as to the calculation of the force boundary, a method in FEM is provided for sabot pressure calculation, base of this, the numerical calculation model is carried out.

给出了弹丸发射强度可靠性计算中的一些理论和概念；给出了串联系统可靠性的逐步线性等效计算方法；将随机有限元方法引入可靠性计算中，建立了弹丸发射时的非线性随机有限元计算模型，并给出了计算中的一些问题的处理方法；在随机有限元的载荷边界的计算中，提出了弹带压力的有限元计算方法和在有限元求解思想上的数值计算模型。

Compared with the conventional model test method and empirical method it is found that the numerical method is more cost-effective and the method is worthy of being advertent and developed.

这一数值计算方法较之传统的实验和经验方法提高了计算分析效率、降低了成本，是一种值得重视和发展的数值计算方法。

A structured grid partitionfor full scale coal fired tangential utility boiler has been given in this paper. It hasa small amount of grids and can decrease false diffusion effectively as it is inagreement with fluid flow direction. Accurate simulating results can be gainedwith the grid partition. Inverse flows are captured near the wall at four corners incombustion simulating through the above grid and temperatures simulating agreewell with them measured.

对于大容量四角切圆锅炉的数值模拟，本文给出了一个可以有效减小伪扩散、流体流动方向与网格线方向一致、数目较少、计算精度较高的结构网格，该网格的数值计算结果清晰得捕捉到了四个角向火侧和背火侧靠近壁面处的小回流，而且计算温度与炉膛温度实测值较好的吻合。

Aiming at the structure and refractive-index profile of wide-angle cross waveguide, the optical field distribution has been calculated by the method.

数值计算对交叉波导的设计和优化有着重要的意义，而选择正确的计算方法是交叉波导数值计算的关键。

In allusion to the characteristic of riblets surface, the computation region, grids and flow parameters were dealt with reasonably, and mechanic similarity principle was brought forwards into fluid field numerical simulation.

针对沟槽表面流场的特点，在数值计算过程中对其计算域、计算网格及其流动参数进行了合理化的处理，并尝试将力学相似原理运用于沟槽表面流场的数值仿真。

The tracer migration that the tracer concentration continuously injecting into semi-infinite sand column(initialization velocity is zero) and the pollutant continuously enter into aquifer through a discharging well that completely enter into the dive aquifer are two representative groundwater pollution problems ,Then this paper respectively sets above two decided solution problems and the union simulation problem of groundwater and solute as examples, from the question description, the mathematical model selection and determination, the parameters selecting to carry on the value computation, the read-write of attribute data , visualizes by the IDL programs, carries on the numerical simulation and the visualization post-processing to the above groundwater pollution problems, and according to the numerical solution and the solute migration curves, briefly analyzes and predicts the temporal and spatial distribution features and distribution range of contaminant concentration.

然后分别以半无限长沙柱中连续注入示踪剂浓度的运移、污染物通过一完全进入潜水层的排放井连续进入含水层这两个典型地下水污染定解问题及地下水流和水质联合模拟问题为例，从问题描述、数学模型选取确定、参数选取到运用IDL编程进行数值计算、属性数据读写、可视化，对上述地下水污染问题进行数值模拟和可视化的后处理，并根据数值模拟的数值结果和溶质运移曲线，对污染物浓度的分布范围及随时空变化趋势作了简要分析预测。

In this paper, the mechanisms of the generation, migration and production for coal seam gas are researched and the geological model for coal seam gas reservoir simulation is presented, according to the theories and methods of coal seam gas geology, petroleum geology and dynamic of fluids through porous media. A three-dimensional, dual-porosity, two-phase, pseudo-steady, non-equilibrium sorption mathematical model is established with the help of petroleum reservoir numerical simulation method. After that, this complex mathematical mode is approximated and solved by finite-difference and fully implicit methods. Coal Seam Gas Reservoir Simulation software in 1. 0 version (CSGRS 1. 0) with Chinese interface of pre-and post-processing function is developed.

本文应用煤层气地质学、石油天然气地质学和渗流力学等学科的理论和方法，研究了煤储层中煤层气的生成、储集、运移和产出机理，概化出了煤层气储层模拟的地质模型；以油气藏数值模拟和数值计算方法为工具，建立了描述三维、双孔隙、非平衡吸附、拟稳态条件下气-水两相流体混相运移规律的煤层气储层模拟的数学模型；详细推导出了该数学模型的全隐式求解方法；并借助计算机技术开发了具有中文操作界面的煤层气储层数值模拟软件CSGRS 1.0，实现了这一复杂数学模型的数值求解。

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。