非牛顿幂律流体绕可渗透平板非定常流动的相似解

文（１）研究了平板表面吸吮速度按照某一规律变化时，非牛顿幂律流体绕可渗透平板非定常流动的运动方程的相似解。本文补充研究吸吮速度按照其它一些规律变化时该问题的准确的或近似的相似解。     

插值摄动法及其在力学中的应用

本文研究了最高阶导数乘以小参数，或出现奇点的微分方程的定解问题，用插值摄动法求得了一级近似解，它和通常的奇异摄动法（匹配法、多尺度法）的一级近似解的精度相同。     

强非线性自激振动问题的瞬态解

用新的改进的L-P法并结合权残法求得了一般情况下(阻尼项可以不是小量)强非线性自激振动问题的一级近似瞬态解。近似解有很好的精度。     

有正阻尼时强非线性自由振动问题的一种解法

在改进的L－P法的基础上,补充考虑振幅的变化,得到了一类有正阻尼的强非线性自由振动问题的一级近似解,近似解有较好的精度。     

保守系统弱非线性振动问题的插值摄动解法

用插值摄动法求得了一类保守系统奇次弱非线性振动问题的一级近似解，精度好，甚至比多尺度法还更好，计算过程简单。     

动力边界元法的正交多项式函数的近似基本解研究

为了克服在用边界元法求解正交各向异性板的动力问题时寻求相应的基本解的困难,本文探讨了二种类型的近似基本解:级数形式及迭加修正形式的近似基本解。前者由正交函数系组成,本文中采用了Hermite正交多项式。后者由相近问题(广义各向同性板静力弯曲问题)的解析基本解迭加上用以修正的级数项组成。一些算例说明了近似基本解方法的可行性和有效性。迭加修正形式的解具有较高精度和较快收敛性,比单纯的级数形式解来得优越。     

组合网架分析的康托洛维奇—加权残数法

本给出的组合网架的一种实用计算方法是用康托洛维奇法把二维平板问题转化成一维问题，而后用加权残数法得到问题的解，计算结果表明，本方法计算简便且有相当的精度，亦可用于一般网架结构的设计。     

组合网架分析的康托洛维奇－加权残数法

本文给出的组合网架的一种实用计算方法是用康托洛维奇法把二维平板问题转化成一维问题，而后用加权残数法得到问题的解，计算结果表明，本文方法计算简便且有相当的精度，亦可用于一般网架结构的设计．     

组合网架分析的康托洛维奇－加权残数法

本文给出的组合网架的一种实用计算方法是用康托洛维奇法把二维平板问题转化成一维问题，而后用加权残数法得到问题的解，计算结果表明，本文方法计算简便且有相当的精度，亦可用于一般网架结构的设计．     

求解等离子体平衡的基映射方法

本文利用基映射方法将不适定的等离子体流函数方程Cauchy问题的解近似表为适定的流函数方程第一边值问题的解的序列。在满足适当精度的要求下将问题进一步归结为求一超定线代数方程组的最优解。应用了Moore,Penrose广义逆阵方法取得了问题的最优最小二乘解。得到了常见的几种非圆位形的数值解及成形场线圈的电流分布。与解析解比较表明,方法的精度是好的。     

A new approximate analytical solution of the ideal potential flow around a circular cylinder between two parallel flat plates

In ref. [1], Lin obtained an approximate analytical solution of the ideal potential flow around a circular cylinder between two parallel flat flates.In this paper, the author shows that one may obtain the result coinciding with that obtained in ref. [1] by making use of the Shvez's method^[2]. Morever, we can obtain a more accurate result than that obtained in ref. [1], if we make use of the improved Shvez's method^[2]. Some calculating examples are presented.     

Thermophoresis in natural convection with variable properties

The present paper deals with thermophoresis in natural convection with variable properties for a laminar flow over a cold vertical flat plate. Variation of properties like density, viscosity and thermal conductivity with temperature is included in the formulation of the problem. Selection of components for the property ratio is made by fitting the property values between the desired temperature limits. For a selected fluid, Prandtl number variation with temperature is neglected and the Prandtl number corresponding to film temperature is used for the analysis. Solution is carried out by finite difference method. Variation of wall concentration and wall flux along the length of plate is studied. The effect of thermophoretic coefficient on wall concentration is also studied. Results are presented in the form of graphs. The result is compared with similarity solution by Runge-Kutta method and found to be accurate upto second decimal place. Received on 18 May 1998     

Hall effects on hydromagnetic flow on an oscillating porous plate

In this paper, an analysis is made on the unsteady flow of an incompressible electrically conducting viscous fluid bounded by an infinite porous flat plate. The plate executes harmonic oscillations at a frequency n in its own plane. A uniform magnetic field Ho is imposed perpendicular to the direction of the flow. It is found that the solution also exists for blowing at the plate. The temperature distribution is also obtained by taking viscous and Joule dissipation into account. The mean wall temperature θo（O） decreases with the increase in the Hall parameter m. It is found that no temperature distribution exists for the blowing at the plate.     

Free convection in a saturated porous medium beyond the similarity solution

The non-similar problems associated with a non-isothermal vertical flat plate embedded in a fluid-saturated porous medium were considered to assess the performances of the two distinctive boundary layer solution methods, namely, the local similarity solution and the integral method. The results generated from these two approximate solution methods are compared against the results from a two-point finite difference and those based on a Merk-type series expansion. Comparison of the results reveals that both integral and local similarity methods perform excellently. Especially, the accuracy acquired by the local similarity solution is so high that the difference between the results from the local similarity solution and those from the two-point finite difference and local non-similarity solution methods is hardly discernible for the case of monotonic increasing wall temperature.     

The solution of large deflection problem of thin circular plate by the method of composite expansion

In this paper, the method of composite expansion in perturbation theory is used for the solution of large deflection problem of thin circular plate. In this method. the outer field solution and the inner boundary layer solution are combined together to satisfy all the boundary conditions. In this paper, Hencky’s membrane solution is used for the first approximation in outer field solution, and then the second approximate solution is obtained. The inner boundary layer solution is found on the bases of boundary layer coondinate. In this paper, the reciprocal ratio of maximum deflection and thickness of the plate is used as the small parameter. The results of this paper improves quite a bit in comparison with the results obtained in 1948 by Chien Wei-zang.     

Some results for approximate strain and rotation tensor formulations in geometrically non-linear Reissner-Mindlin plate theory

Finite element deflection and stress results are presented for four flat plate configurations and are computed using kinematically approximate (rotation tensor, strain tensor or both) non-linear Reissner-Mindlin plate models. The finite element model is based on a mixed variational principle and has both displacement and force field variables. High order interpolation of the field variables is possible through p-type discretization. Results for some of the higher order approximate models are given for what appears to be the first time. It is found that for the class of example problems examined, exact strain tensor but approximate rotation tensor theories can significantly improve the solution over approximate strain tensor models such as the von Kármán and moderate rotation models when moderate deflections/rotations are present. However, for each of the problems examined (with the exception of a postbuckling problem) the von Kármán and moderate rotation model results compared favorably with the higher order models for deflection magnitudes which could be reasonably expected in typical aeroelastic configurations.     

基于整体位移模式的平面裂纹结构数值模拟方法

对于平面裂纹问题,针对扩展有限元法和无网格伽辽金法的不足,从结构的整体位移模式出发,提出了一种新的数值模拟方法。在整个求解域内构造其试探函数,并引入裂纹修正项描述裂尖处的奇异性和裂纹面的强间断特性;同时,提出了一种新的强制边界条件施加方法,通过引入位移边界水平集函数,将位移边界条件包含在近似位移场的表达式中,有效地解决了位移边界条件问题,减小了刚度矩阵的阶数,非常方便地消除了刚度矩阵的奇异性,降低了线性方程组的求解难度。含裂纹矩形平板结构的数值算例验证了该方法的有效性。     

Numerical solution of natural convection flow past a non-isothermal vertical flat plate

The problem of natural convection over a semi-infinite flat plate with non-uniform wall temperature is studied by using a numerical method. The local rates of heat transfer as a function of the distance along the plate are tabulated for a range of Prandtl numbers (0.01 to 100) and for a few cases of wall temperature distributions. Such tabulations serve as a reference against which other approximate solutions can be compared in the future.