非数值计算

Scattering characteristics are studied of inhomogeneous cylinders immersed in an absorbing medium illuminated normally by plane waves. Scattering and extinction cross sections are derived, and the efficient algorithm is presented. Scattering matrix is simulated and discussed.

系统地解决了吸收介质中非均匀柱粒子对垂直入射平面波的散射问题，包括散射场、散射截面、消光截面的解析解，提出了快速、有效的计算方法；数值模拟了均匀、非均匀圆柱的散射矩阵，并与已有文献发表结果对比。

A pressure correction equation is established by use of the finite volume method on nonorthogonal collocated grids, and its algebraic form is also given. The equation is applied to simulation of the flow field in an equilateral cavity and an inclined cavity with a tilt angle of 45°.

利用有限体积法建立了非正交同位网格系统中的压力校正方程，详细给出了压力校正方程的离散形式，并对正方腔及倾斜角为45°的斜方腔内流场进行了数值模拟计算。

This paper uses numerical simulation technique to simulate unstable temperature field in the process of bimetallic composite casting.

应用数值模拟技术对双金属复合过程中的非稳态温度场进行计算。

The introduced model can simulate both the steady state and the transient temperature field of the top surface of the thermal sensitive layer on a bolometer detector.

本文主要介绍用有限元数值分析的方法对非致冷红外测辐射热计探测器的温度分布进行计算，其有限元模型可以对测辐射热计探测器热敏层表面的稳态和瞬态温度场进行仿真。

The numerical experiments demonstrated that, on the case that only a half of the information of the whole microstructure is used, FDHMM can effectively simulate the transient unsaturated water flow in the specific soils, FDHMM with the Dirichlet boundary condition for cell problem can offer a big saving in the computational cost.

数值实验表明：在仅使用一半微观信息的情况下，FDHMM能够有效地模拟特定土壤中的非稳定非饱和水流问题，单胞问题使用Dirichlet边界条件的FDHMM能大幅度地节省计算费用。

Euler equation ; chemical non equilibrium ; inviscid flow ; numerical simulation ; computational method

欧拉方程；化学非平衡；无粘绕流；数值模拟；计算方法

Furthermore, the first-order optimality condition and its equivalent reformulations for generalized semi-infinite max-min programming with a non-compact set are presented using the lower-Hadamard directional derivative and subdifferential.2. Chapter 3 studies the gradient-type methods for unconstrained optimization problems. Section 1 proposes a new class of three-term memory gradient methods. The global convergence property of the method is established. Furthermore, in order to improve the convergence property of the method, a new class of memory gradient projection methods is presented with the property that the whole sequence of iterates converges to a solution to the problem under the conditions such as pseudo-convexity and continuous differentiability of objective function. In section 2, two new classes of methods, called gradient-type method with perturbations and hybrid projection method with perturbations, are proposed. In these methods, non-monotone line search technique is employed, which makes them easily executed in computer.

第3章研究了无约束优化问题的梯度型算法，第1节提出了一类新的三项记忆梯度算法，讨论了算法的全局收敛性，进一步提出了一类新的具有更好收敛性质的记忆梯度投影算法，并证明了该算法在函数伪凸的情况下具有整体收敛性，第2节在非单调步长搜索下提出了带扰动项的梯度型算法及其混合投影算法，这两类算法的一个重要特征就是步长采用线搜索确定而不象许多文献中那样要求步长趋于零，这样更容易在计算机上实现，在较弱的条件下证明了这些算法的全局收敛性，数值算例表明了算法的有效性。

Therefore, the primary purpose of the present study is to construct the projection methods in higher order accuracy. Furthermore, the proposed projection methods will be applied to nonstaggered grids, curvilinear coordinates, and moving mesh cases.

因此，本文从提高数值方法计算精度入手，构造了高阶时间精度的投影方法，并将投影方法推广到非交错网格和一般坐标系及动网格中。

Cavity flows both with and without sound excitation are studied by solving the 2 D time dependent Reynolds averaged Navier Stokes equations using explicit predictor corrector difference algorithm of Mac Cormack.

采用显式MacCorma－ck二步预估校正有限差分格式，求解二维雷诺平均非定常Navier－Stokes方程；并用Cebeci－Smith代数紊流模型作适当修正来模拟紊流效应，对有、无前缘声激励两种情况的空腔流场作了数值模拟，计算的振荡频率及振荡幅值都与实验结果基本符合，并且较好地模拟出了声激励对流场的影响。

Since the interface is treated as an internal flow field so it can accurately keep the conservation of flow variables on the sliding interface. Both laminar and turbulent unsteady rotor/stator interaction of a turbine stage with arbitrary pitch ratio are calculated successfully.

成功地计算了小雷诺数工况下具有任意栅距比的轴流动/静相干叶排内部非定常层流流动，及采用标准K-ε两方程模型对较大雷诺数工况下动/静相干轴流叶排内部非定常紊流流动进行了数值分析。

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。