具有未知源的某些非线性伪抛物型方程的反问题

考 虑具有未 知源项的 某些非 线性伪 抛物 型方程 的反演 问题． 首先 将伪抛 物型 方程初 边值问 题化为非线 性发展方 程 Ｃｏｕｃｈ ｙ 问题，然 后，利用半 群理论，论 证发展 方程反问 题解的存 在唯一 性，最后， 利用不 动点方法得到 伪抛物型方程反 问题的可解性     

线性对流占优Sobolev方程的流线扩散有限元方法

Abastract. In this paper,a streamline-diffusion F. E. M. for linear Sobolev equations with con-vection-dominated term is given. According to the range of space-time F. E mesh parameter h,two choices for artifical diffusion parameter are presented,and for the corresponding computa-tion schemes the stability and error estimates in suitable norms are estabilished.     

渗流耦合系统动边值问题特征分数步差分方法

对多层渗流方程耦合系统动边值问题,提出适合并行计算的一类特征分数步差分格式,利用区域变换、变分形式、粗细网格配套、乘积型叁二次插值、差分算子乘积交换性、高阶差分算子的分解、先验估计的理论和技巧,得到收敛性的最佳阶l2误差估计.该方法已成功地应用到多层油资源运移聚集的资源评估生产实际中,得到了很好的数值模拟结果.     

Modified characteristic finite difference fractional step method for moving boundary value problem of nonlinear percolation system

A fractional step scheme with modified characteristic finite differences running in a parallel arithmetic is presented to simulate a nonlinear percolation system of multilayer dynamics of fluids in a porous medium with moving boundary values. With the help of theoretical techniques including the change of regions, piecewise threefold quadratic interpolation, calculus of variations, multiplicative commutation rule of difference operators, multiplicative commutation rule of difference operators, decomposition of high order difference operators, induction hypothesis, and prior estimates, an optimal order in l ² norm is displayed to complete the convergence analysis of the numerical algorithm. Some numerical results arising in the actual simulation of migration-accumulation of oil resources by this method are listed in the last section.     

AN ADI GALERKIN METHOD WITH MOVING FINITE ELEMENT SPACES FOR A CLASS OF SECOND-ORDER HYPERBOLIC EQUATIONS

1　 IntroductionADI Galerkin methods were first formulated for the solution of nonlinear parabolic andlinear second-order hyperbolic problems on rectangular regions by Douglas and Dupont[1 ] .These methods combine alternating-direction method and Galerkin finite element methodtogether.So,they have the advantage of reducing the solution of a multidimensional problemto the solution of sets of independent one-dimensional problems,decreasing the amount ofcalculation,natural parallelism and highe…     

带有对流项的拟线性Sobolev方程的差分-流线扩散法

1　引　　言流线扩散法 (Stream line- Diffusion method,简称 SD方法 )是由 Hughes和 Brooks在文献 [1]中提出 ,并由 Johnson等人 (文献 [2 ]- [4])发展起来的求解对流占优扩散问题 (包括双曲型问题 )的一种有效的数值方法 .SD方法兼具有良好的数值稳定性和高阶收敛精度已广泛地应用于计算流体等诸多问题 .然而 ,传统的 SD方法均采用时空有限元求解发展型问题 .这样 ,虽可使时间和空间方向上的精度很好的协调起来 ,却增大了实际计算的复杂程度 ;对非线性问题也不便进行线性化处理 .孙澈等人在文献 [5 ]中对对流扩散问题提出了仅对空间…     

一非线性发展方程的反问题

研究一非线性发展方程的未知源项的反演问题.首先，把所考虑的初边值问题化成一等价非线性发展方程的Cauchy问题；然后，利用半群理论，论证反问题解的存在性和唯一性；最后，利用压缩映射不动点方法，得到反问题的可解性.