ERROR ANALYSIS OF NONLINEAR GALERKIN METHODS FOR KURAMOTO-SIVASHINSKY EQUATIONS

Nonlinear Galerkin methods are new schemes for integrating dissipative systems:In the present paper, we obtain the estimates to the rate of convergence of such methods for Kuramoto-Sivashinsky equations. In particular, by an illustrative example, we show that nonlinear Galerkin methods converge faster than the usual Galerkin method.     

非线性Galerkin算法的收敛性和复杂性

本文给出了数值求解非线性发展方程的全离散非线性Ｇａｌｅｒｋｉｎ算法,即将空间离散时的谱非线性Ｇａｌｅｒｋｉｎ算法和时间离散的Ｅｕｌｅｒ差分格式相结合,得到了显式和隐式两种全离散数值格式,相应地也考虑了显式和隐式的Ｇａｌｅｒｋｉｎ全离散格式,并分别分析了上述四种全离散格式的收敛性和复杂性,经过比较得出结论;在某些约束条件下,非线性Ｇａｌｅｒｋｉｎ算法和Ｇａｌｅｒｋｉｎ算法具有相同阶的收敛速度,然而前     

非线性Sobolev方程Galerkin解法的后处理与超收敛

研究非线性Sobolev方程Galerkin解法的后处理与超收敛．对半离散及全离散格式,证明了当有限元空间次数,r≥2时,有限元解经过后处理,H1-模和L2-模误差估计可分别提高一阶．     

Long time stability and convergence for fully discrete nonlinear galerkin methods

The aim of this paper is to analyze the fully discrete nonlinear Galerkin methods, which are well suited to the long time integration of dissipative partial differential equations.

With the help of several time discrete Gronwall lemmas, we are able to prove L ^∞(IR⁺,H ^α ) (α=0,1) stabilities of the fully discrete nonlinear Galerkin methods under a less restrictive time step constraint than that of the classical Galerkin methods.     

The spectral method for the flow between two concentric rotating spheres, part II: The full discrete nonlinear Legendre-Galerkin method

The nonlinear Galerkin methods are numerical schemes for evolutionary partial differential equations based on the theory of inertial manifolds and approximate inertial manifolds. In this paper, we consider the flow between two concentric rotating spheres, and combine the Legendre-Galerkin spectral methods in Part I together with the nonlinear Galerkin method, then construct the full discrete nonlinear Legendre-Galerkin spectral scheme, and derive the stability conditions and its error estimate.     

Galerkin methods in time for semi-discrete viscoelastodynamics

In semi-discrete nonlinear elastodynamics, higher order energy and momentum conserving time stepping schemes turned out to be well suited for computing long time motions [1]. In comparison to standard ODE integrators, conserving schemes exhibit superior stability properties which are of utmost importance in a nonlinear .nite element framework. We show that conserving schemes are particularly well suited as starting point for the development of energy consistent schemes for dissipative dynamical systems. In particular, viscoelastic material behaviour is considered. A key advantage of energy consistent schemes lies in the fact that the equilibrium state of viscoelastic systems can be de.nitely reached, independent of the material parameters. In the paper, we compare two Galerkin methods for the temporal discretisation of semi-discrete nonlinear viscoelastodynamics: the standard continuous Galerkin (cG) method and an enhanced continuous Galerkin (eG) method which ful.ls the total energy balance exactly. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

关于K-S方程的非线性伽辽金方法(英文)

该文讨论了关于 K- S方程的伽辽金方法和非线性伽辽金方法的收敛性和 L2 误差估计 ,并得出误差阶一致的结论     

A NONLINEAR GALERKIN METHOD WITH VARIABLE MODES FOR KURAMOTO-SIVASHINSKY EQUATION

1.IntroductionThenonlinearGalerkinmethodwasintroducedbyMarionandTemaml4],whichisstemmedfromthetheoryofinertialmanifoldsanddynamicalsystemtheory.The'considerableincreaseinthecomputingpowerduringlastyearsmakesitpossibleforthemathematicianstosolvenumeri...     

High-order convergent deferred correction schemes based on parameterized Runge–Kutta–Nyström methods for second-order boundary value problems

Iterated deferred correction is a widely used approach to the numerical solution of first-order systems of nonlinear two-point boundary value problems. Normally, the orders of accuracy of the various methods used in a deferred correction scheme differ by 2 and, as a direct result, each time deferred correction is used the order of the overall scheme is increased by a maximum of 2. In [16], however, it has been shown that there exist schemes based on parameterized Runge–Kutta methods, which allow a higher increase of the overall order. A first example of such a high-order convergent scheme which allows an increase of 4 orders per deferred correction was based on two mono-implicit Runge–Kutta methods. In the present paper, we will investigate the possibility for high-order convergence of schemes for the numerical solution of second-order nonlinear two-point boundary value problems not containing the first derivative. Two examples of such high-order convergent schemes, based on parameterized Runge–Kutta-Nyström methods of orders 4 and 8, are analysed and discussed.     

Centred TVD schemes for hyperbolic conservation laws

New first- and high-order centred methods for conservation lawsare presented. Convenient TVD conditions for constructing centredTVD schemes are then formulated and some useful results areproved. Two families of centred TVD schemes are constructedand extended to nonlinear systems. Some numerical results arealso presented.     

A TVD Type Wavelet-Galerkin Method for Hamilton-Jacobi Equations

In this paper,we use Daubechies scaling functions as test functions for the Galerkin method,and discuss Wavelet-Galerkin solutions for the Hamilton-Jacobi equations.It can be proved that the schemesare TVD schemes.Numerical tests indicate that the schemes are suitable for the Hamilton-Jacobi equations.Furthermore,they have high-order accuracy in smooth regions and good resolution of singularities.     

Boundary element methods for potential problems with nonlinear boundary conditions

Galerkin boundary element methods for the solution of novel first kind Steklov-Poincaré and hypersingular operator boundary integral equations with nonlinear perturbations are investigated to solve potential type problems in two- and three-dimensional Lipschitz domains with nonlinear boundary conditions. For the numerical solution of the resulting Newton iterate linear boundary integral equations, we propose practical variants of the Galerkin scheme and give corresponding error estimates. We also discuss the actual implementation process with suitable preconditioners and propose an optimal hybrid solution strategy.

     

On Nonlinear Galerkin Approximation

1.IntroductionInordertosolvetheproblemoflongtimeilltegrationofevolutionpartialdifferentialequations,nPnlinearGalerkinmethodsareintroducedinrecentyears.SuchmethodsstemfromthetheoryofinertialmanifoldsandaPprokimateinertialmanifolds.Werecallaninertialmanifoldisafinitedimensionalsmoothmanifoldwhichcontainstheglobalattractora-ndattractseveryorbitatanexponelltial.ate[1'2].However,therearestillmanydissipativepartialdifferelltialequationsforwhichtheexistenceofinertialmanifoldsisnotknown;thereareeven…     

GLOBAL FINITE ELEMENT NONLINEAR GALERKIN METHOD FOR THE PENALIZED NAVIER-STOKES EQUATIONS GLOBAL FINITE ELEMENT NONLINEAR GALERKIN METHOD FOR THE PENALIZED NAVIER-STOKES EQUATIONS

1. IntroductionIn the numerical simulation of the Navier-Stokes equations one encounters three seriousdifficulties in the case of large Reynolds numbers f the treatment of the incomPressibility con-dition divu = 0, the treatment of the noIilinear terms and the large time integration. For thetreatment of the incoInPressibility condition, one use the penalty method in the case of finiteelemellts [1--2l and for the treatmen of the noulinar terms and the large tfor integration, oneuse the nonlin…     

Comparison of generalized differential quadrature and Galerkin methods for the analysis of micro-electro-mechanical coupled systems

This paper presents a comprehensive comparison study between the generalized differential quadrature (GDQ) and the well-known global Galerkin method for analysis of pull-in behavior of nonlinear micro-electro-mechanical coupled systems. The nonlinear governing integro-differential equation for double clamped MEMS devices which was derived using variational principle by the authors [Sadeghian H, Rezazadeh G, Osterberg PM. Application of the generalized differential quadrature method to the study of pull-in phenomena of MEMS switches. J Microelectromech Syst 2007;16(6):1334–40] is discretized by applying Galerkin and GDQ methods. The divergence instability or pull-in phenomenon is analyzed. Obtained results are compared with the results of the pervious works. The Galerkin method is implemented with effect of number of used shape functions. Different types of trail functions on calculated pull-in voltage are examined.Furthermore, compare to one term and two terms truncation Galerkin method, it is observed that the GDQ with small number of grid points (non-uniform) performs accurate results for nonlinear micro-electro-mechanical coupled behavior which requires a large number of grid points at high-order approximation.     

STABILITY ANALYSIS OF NONLINEAR GALERKIN ＆ GALERKIN METHODS FOR NONLINEAR EVOLUTION EQUATIONS

Abstract. Ogr object in this artlcle is to describe tbe Galerkln scheme and nonlin-eax Galerkin scheme for the approximation of nonlinear evolution equations, and tostudy the stability of these schemes. Spatial discretizatlon can be pedormed by eitherGalerkln spectral method or nonlinear Galerldn spectral method; time discretizatlort isdone hy Euler sin.heine wklch is explicit or implicit in the nonlinear terms. According tothe stability analysis of the above schemes, the stability of nonllneex Galerkln methodis better than that of Galexkln method.     

An analytical method for approximating high-order Galerkin solutions

The high-order Galerkin procedures for computing forced oscillations of nonlinear systems are generally impractical to apply analytically. In this paper, an analytical method for approximating high-order Galerkin solutions is presented, which is applicable to ordinary differential equations with polynomial nonlinearities. The procedure is restricted to oscillations whose predominant Fourier component is the fundamental; hence subharmonic oscillations may be allowed, whereas superharmonic oscillations are excluded. The approach taken is to consider only the first-order effects of the higher harmonics. An example is given which demonstrates that the accuracy of the method can be quite impressive.     

车路耦合非线性振动高阶Galerkin截断研究

将移动车辆模型化为运动的两自由度质量-弹簧-阻尼系统,道路模型化为立方非线性黏弹性地基上的弹性梁,并将路面不平度设定为简谐函数．通过受力分析,建立车路非线性耦合振动高阶偏微分方程．采用高阶Galerkin截断结合数值方法求解耦合系统的动态响应．首次研究不同截断阶数对车路耦合非线性振动动态响应的影响,确定Galerkin截断研究车路耦合振动的收敛性．研究结果表明,对于软土地基的沥青路面,耦合振动的动态响应,需要150阶以上的截断才能达到收敛效果．并通过高阶收敛的Galerkin截断研究了系统参数对车路耦合非线性振动动态响应的影响.     

High-order accurate thin layer approximations for time-domain electromagnetics. Part I: General metal backed coatings

We present a family of high-order accurate thin layer approximations for time-domain electromagnetics. The thin layer approximations are valid for metal backed coatings of general isotropic materials and certain classes of anisotropic materials on smooth curvilinear backgrounds. Both dielectric and magnetic materials can be considered. These models are non-trivial and we discuss their properties and implementation in the context of discontinuous Galerkin methods which are particularly well suited for these models. The range of validity, accuracy, and stability of the resulting schemes is demonstrated through one- and two-dimensional examples.     

NONLINEAR GALERKIN METHODS FOR SOLVING TWO DIMENSIONAL NEWTON－BOUSSINESQ EQUATIONS

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