一些非线性发展方程的Fourier方法

建立在三角插值基础上的配置方法叫作Fourier方法(或拟谱方法)。三角插值具有很好的逼近性质,这使得Fourier方法成为一种高精度的数值方法。自Kreiss和Oliger1972年提出Fourier方法后,此方法便广泛地应用于偏微分方程周期解的计算上(例如见[6,7,8,9,10]),[2,7,9,10]给出了线性问题半离散方法的稳定性结果,[2,10]还研究了对非光滑初值的磨光方法。[3]对于线性变系数双曲方程,给出了对于     

On Steady States and Its Capturing Schemes for Shallow-Water Equations with Source Terms

Consider the shallow fiuid fiow in a ehannel with wavy bottom,whieh 15 governed by thefollowing equations:h‘+(h。)二=0,(h。)‘+(hoZ+夕hZ/2)二=一夕hB‘(x),(1)where h denotes the hight of the fluid above the wavy bottom eharaeterized by a funetionB(二)and 0 15 the horizontal veloeity of the fluid.It 15 not diffieult to show that every steadystate(i.e.,asympototie solution)of(1)obeys the following balanee eonditions: h(x)。(x)=eonst.,uZ(x)/2+夕h(x)+夕刀(x)=eonst.(2)and that when h and 0 are smo…     

DISSIPATIVE SCHEMES WITH PROPERTY OF INHERITING HOMOCLINIC ORBITS FOR 2N-DIMENSIONAL HAMILTONIAN SYSTEMS

1　ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｉｓｐａｐｅｒｉｓｄｅｖｏｔｅｄｔｏｓｔｕｄｙｗｈａｔｋｉｎｄｏｆｄｉｓｃｒｅｔｅｓｃｈｅｍｅｓｏｆｔｈｅｆｏｌｌｏｗｉｎｇ 2ｎ ｄｉｍｅｎ ｓｉｏｎａｌＨａｍｉｌｔｏｎｉａｎｓｙｓｔｅｍｓｗｉｔｈｐａｒａｍｅｔｅｒｉｎｎｏｒｍａｌｆｏｒｍ ｕ=Ｊ2ｎ Ｈ ｕＴ,　　Ｈ =Ｈ(ｕ ,λ) ,(1 )ｗｈｅｒｅｕ∈Ｒ2ｎ,λ∈Ｒ ,Ｈ∈Ｃｋ+1(Ｒ2ｎ×Ｒ ,Ｒ) ,ｋ≥ 6,ａｎｄＪ2ｎ =0Ｉｎ-Ｉｎ 0 ,Ｉｎ:ｕｎｉｔｍａｔｒｉｘｏｆｏｒｄｅｒｎｈａｓｔｈｅｐｒｏｐｅｒｔｙｏｆｉｎｈｅｒｉｔｉｎｇｈｏｍ…     

关于半离散Galerkin近似解的L_∞估计的一个注记

在《计算数学》和《高等学校计算数学学报》上最近发表的文章[1]和[2]中,分别讨论了抛物和二阶双曲方程半离散Galerkin近似解(分片线性函数情形)的L_∞估计。文章作者采用正则Green函数方法证明了阶为h~2ln(1/h)的误差估计式。值得指出,[1]和[2]中所给出的估计式的一个不足之处就是它们所需要的精确解的正则性过于强。在这个注记里,我们将说明如下事实,利用熟知的半离散Galerkin近似解的超收敛估计和有限元函数空间的一个弱嵌入性质,可以证明得到阶也是h~2ln(1/h)的误差估计式,然而对解的正则性的要求则较[1]和[2]中估计式所需要的弱得多。 先讨论抛物问题,文[1]讨论的是热传导问题     

一类含有参数和有理奇性哈密顿系统的同宿与异宿轨道

研究一类含有两个参数和有理奇性平面哈密顿系统的同宿与异宿轨道,该问题来源于一个关于聚合物流体剪切流动特性的研究．借助常微定性理论和不变流形分析的方法,文中给出了系统存在同宿与异宿轨道的条件,并通过数值计算检验了所得理论结果。     

Hopf Bifurcation for Non—smooth Planar Dynamical Systems

The purpose of this paper is to study the Hopf bifurcation property of the non-smooth planar dynamical systemwhere the individual functions K± R2 x I R2 at the right-hand side for some interval I containing 0 are smooth enough and given byThe parameter dependent matrices Aa(A) are assumed to be of the formwhere a 0 and w±() > 0. And the nonlinear terms in equation (??) are assumed to be smooth enough and have the formIn a standard way we extend the system (??) to a differential inclusion …     

Positive Entire Solutions to an Elliptic System

Ｉｎａｒｅｃｅｎｔｐａｐｅｒ [1],ＹｅｈａｓｄｅｍｏｎｓｔｒａｔｅｄｔｈａｔｔｈｅｓｉｎｇｕｌａｒｎｏｎｌｉｎｅａｒｅｌｌｉｐｔｉｃｅｑｕａｔｉｏｎΔｕ =ｆ(ｕ , ｕ ,ｘ ) /ｕλ,　ｘ∈Ｒ2 ,0 <λ<1ｈａｓａｐｏｓｉｔｉｖｅｅｎｔｉｒｅｓｏｌｕｔｉｏｎｕｎｄｅｒｓｏｍｅｃｏｎｄｉｔｉｏｎｓｉｍｐｏｓｅｄｏｎｆ.Ｐｒｏｂｌｅｍｓｏｆｆｉｎｄｉｎｇｐｏｓｉｔｉｖｅｅｎｔｉｒｅｓｏｌｕｔｉｏｎｓｔｏｅｌｌｉｐｔｉｃｅｑｕａｔｉｏｎｓｈａｖｅｂｅｅｎｓｔｕｄｉｅｄｂｙｍａｎｙａｕｔｈｏｒｓｓｉｎｃｅｔｈｅｙｈ…     

Generalized Hopf Bifurcation for Non-smooth Planar Dynamical Systems： the Corner Case

Piece-wise smooth systems are an important class of ordinary differential equations whosedynamics are known to exhibit complex bifurcation scenarios and chaos. Broadly speaking,piece-wise smooth systems can undergo all the bifurcation that smooth ones can. Moreinterestingly, there is a whole class of bifurcation that are unique to piece-wise smoothsystems, such as the bifurcation caused by the geometric shape of the region in which thevector field is analyzed. For example (see Figure 1), the region is divided into two partsI and Ⅱ by a discontinuity boundary which contains a corner at O. When an orbit crossthe corner, border-collision bifurcation may occur (cf. [1]). The present paper deals withthe mechanics of the generalized Hopf bifurcation when the stationary point locates at thecorner.