FOURIER－CHEBYSHEV SPECTRAL METHOD FOR SOLVING THREE－DIMENSIONAL VORTICITY EQUATION

ＦＯＵＲＩＥＲ－ＣＨＥＢＹＳＨＥＶＳＰＥＣＴＲＡＬＭＥＴＨＯＤＦＯＲＳＯＬＶＩＮＧＴＨＲＥＥ－ＤＩＭＥＮＳＩＯＮＡＬＶＯＲＴＩＣＩＴＹＥＱＵＡＴＩＯＮＧＵＯＢＥＮＹＵ（郭本瑜）；ＬＩＪＩＡＮ（李健）；ＭＡＨＥＰＩＮＧ（马和平）（Ｄｅｐａｒｔｍｅｎｔｏ...     

THE ERRORS ESTIMATION OF THE CHEBYSHEV SPECTRAL－DIFFERENCE METHOD FOR TWO－DIMENSIONAL VORTICITY EQUATION

ＴＨＥ　ＥＲＲＯＲＳ　ＥＳＴＩＭＡＴＩＯＮ　ＯＦ　ＴＨＥ　ＣＨＥＢＹＳＨＥＶ　ＳＰＥＣＴＲＡＬ－ＤＩＦＦＥＲＥＮＣＥ　ＭＥＴＨＯＤ　ＦＯＲ　ＴＷＯ－ＤＩＭＥＮＳＩＯＮＡＬ　ＶＯＲＴＩＣＩＴＹ　ＥＱＵＡＴＩＯＮＴＨＥＥＲＲＯＲＳＥＳＴＩＭＡＴＩＯＮＯＦ...     

THE FOURIER PSEUDOSPECTRAL METHOD FOR THREE-DIMENSIONAL VORTICITY EQUATIONS

This paper develops the Fourier Pseudospectral Method to solve three-dimensional vorticity equations.The generalized stability is proved,from which the convergence follows with some assumptions.     

NONCONFORMING FINITE ELEMENT PENALTY METHOD FOR STOKES EQUATION

a special penalty method is presented to improve the accuracy of the standard penaltymethod (or solving Stokes equation with nonconforming finite element, It is shown that thismethod with a larger penalty parameter can achieve the same accuracy as the staodaxd methodwith a smaller penalty parameter. The convergence rate of the standard method is just hall order of this penalty method when using the same penalty parameter, while the extrapolationmethod proposed by Faik et al can not yield so high accuracy of convergence. At last, we alsoget the super-convergence estimates for total flux.     

COMBINED FINITE ELEMENT AND PSEUDOSPECTRAL METHOD FOR THE THREE-DIMENSIONAL NAVIER-STOKES EQUATIONS

This paper analyzes a combined method with artificial compression for solving thethree-dimensional evolutionary Navier-Stokes equations with periodic and no-slipboundary condition.A Fourier pseudospectral method with a control operator is used inthe periodic direction and a standard finite element method in the two others.The gener-alized stability of the scheme and optimal rate of convergence of the velocity in L~2-normare proved on the assumption that the BB condition of the fiinite element approximation forthe two-dimensional Stokes equations is satisfied.     

CHEBYSHEV PSEUDOSPECTRAL DOMAIN DECOMPOSITION METHOD OF ONE－DIMENSIONAL ELLIPTIC PROBLEMS

ＣＨＥＢＹＳＨＥＶＰＳＥＵＤＯＳＰＥＣＴＲＡＬＤＯＭＡＩＮＤＥＣＯＭＰＯＳＩＴＩＯＮＭＥＴＨＯＤＯＦＯＮＥ－ＤＩＭＥＮＳＩＯＮＡＬ　ＥＬＬＩＰＴＩＣ　ＰＲＯＢＬＥＭＳＸｉｏｎｇＹｕｅｓｈａｎ（Ｄｅｐｔ，ｏｆＭａｔｈ．，ＮａｔｉｏｎａｌＵｎｉｖ．ｏｆＤ...     

CHEBYSHEV PSEUDOSPECTRAL-HYBRID FINITE ELEMENT METHOD FOR THREE-DIMENSIONAL VORTICITY EQUATION

In this paper,Chebyshev pseudospectral-finite element schemes are proposed for solving three dimensional vorticity equation.Some approximation results in nonisotropic Sobolev spaces are given.The generalized stability and the convergence are proved strictly.The numerical results show the advantages of this method.The technique in this paper is also applicable to other three-dimensional nonlinear problems in fluid dynamics.     

DISCONTINUOUS GALERKIN FINITE ELEMENT METHOD FOR A FORWARD-BACKWARD HEAT EQUATION

A space-time finite element method,discontinuous in time but continuous in space, is studied to solve the nonlinear forward-backward heat equation. A linearized technique is introduced in order to obtain the error estimates of the approximate solutions. And the numerical simulations are given.     

AN ITERATIVE ALGORITHM FOR DETERMINING TIME－DEPENDENT COEFFICIENT OF TWO DIMENSIONAL LINEAR WAVE EQUATION

ＡＮＩＴＥＲＡＴＩＶＥＡＬＧＯＲＩＴＨＭＦＯＲＤＥＴＥＲＭＩＮＩＮＧＴＩＭＥ－ＤＥＰＥＮＤＥＮＴＣＯＥＦＦＩＣＩＥＮＴＯＦＴＷＯＤＩＭＥＮＳＩＯＮＡＬＬＩＮＥＡＲＷＡＶＥＥＱＵＡＴＩＯＮ（苏超伟）西北工业大学，邮编：７１００７２ＳｕＣｈａｏｗｅｉ（Ｎ...     

FOURIER PSEUDOSPECTRAL-FINITE DIFFERENCE METHOD FOR TWO-DIMENSIONAL VORTICITY EQUATION

A Fourier pseudospectral-finite difference sheme is proposed for solving two-dimensional vorticity equations.The generalized stability and the convergence are proved.The numerical results are given.     

求解二维Fisher-KPP方程的一类保正保界差分格式及其Richardson外推法

本文研究求解二维Fisher-Kolmogorov-Petrovsky-Piscounov (Fisher-KPP)方程的一类保正保界差分格式.运用能量分析法证明了当网格比满足$R_{x}+R_{y}+[b\tau (p-1)]/2\leq\frac{1}{2}$时差分解具有一系列数学性质,包括保正性、保界性和单调性,且在无穷范数意义下有$O (\tau+h_{x}^{2}+h_{y}^{2})$的收敛阶.然后通过发展Richardson外推法得到收敛阶为$O (\tau^{2}+h_{x}^{4}+h_{y}^{4})$的外推解.最后数值实验表明数值结果与理论结果相吻合.值得提及的是在运用本文构造的Richardson外推法时对时空网格比没有增加更严格的条件.     

对流扩散方程的一种新型差分格式

对流扩散方程可以描述众多的物理化学现象，因而对其寻求稳定的，实用的数值解法有着重要的现实意义。本文针对形式较一般的一维非定常对流扩散方程，构造了对角元严格占优的Crank-Nicholson差分格式，然后对其分别用分离变量的方法以及能量估计的方法作了稳定性的分析，最后给出了数值试验的结果，数值结果表明本文构造的格式能够较好的处理经典的Crank-Nicholson格式所不能处理的对流项系数较大的对流扩散方程，并具有较好的精度。     

对称正则长波方程的守恒差分算法

1引言SRLW方程(?)~3u/(?)x~2(?)t-(?)u/(?)t=(?)p/(?)x u((?)u/(?)x),(1.1) (?)p/(?)t (?)u/(?)x=0(1.2)是正则长波(RLW)方程的一种对称叙述,用于描述弱非线形作用下空间电荷的等离子声     

二维线性双曲型方程Neumann边值问题的紧交替方向隐格式

对二维Neumann边界条件的线性双曲型方程建立了紧交替方向的隐格式.利用方程和边界条件得到在空间上的三阶与五阶导数的边界值,进而在内点、边界内点和边界角点分别建立9点、6点和4点紧差分格式;通过引进新的范数和L₂范数估计L_∞范数;借助能量估计、Gronwall不等式和Schwarz不等式等技巧,详细分析了差分格式在无穷范数下关于时间和空间分别为二阶和四阶收敛性,并给出了稳定性结果;通过数值算例,验证了理论分析结果.     

CHEBYSHEV SPECTRAL-FINITE ELEMENT METHOD FOR TWO-DIMENSIONAL UNSTEADY NAVIER-STOKES EQUATION

1. IntroductionSpectral method has been used successfu11y in computational fluid dynamics. FOr semi-periodic problems, we can use mixed FOurier-Chebyshev spectral method, FOurier spectral-finitedifference method and FOurier spectral-finite element method …     

求解对流扩散方程的ICT-MMOCAA差分解法

Combing the ideas of FCT^[1,2]with the MMOCAA^[3],the ICT-MMOCAA difference method,in which the transport is corrected by interpolation,is established for convection diffusion problem in the paper,The new method possesses the property of general FCT schemes and it is free from oscillation,with which the large gradient problem is solved by the MMOCAA difference method based on high-order(≥2)Lagrange interpolation^[3].Because the analysis in [3]is only suit for the scheme based on linear interpolation,the analysis method difered form [3] is used for obaining the error estimates of the new method.The numerical example is given in the paper.     

COMPACT FOURTH-ORDER FINITE DIFFERENCE SCHEMES FOR HELMHOLTZ EQUATION WITH HIGH WAVE NUMBERS

In this paper, two fourth-order accurate compact difference schemes are presented for solving the Helmholtz equation in two space dimensions when the corresponding wave numbers are large. The main idea is to derive and to study a fourth-order accurate compact difference scheme whose leading truncation term, namely, the O（h^4） term, is independent of the wave number and the solution of the Helmholtz equation. The convergence property of the compact schemes are analyzed and the implementation of solving the resulting linear algebraic system based on a FFT approach is considered. Numerical results are presented, which support our theoretical predictions.     

A FOURIER SPECTRAL SCHEME FOR SOLVING NONLINEAR KLEIN-GORDON EQUATION

A Fourier spectral scheme is proposed for solving the periodic problem of nonlinear Klein-Gordon equation. Its stability and convergence are investigated. Numerical results are also presented.