Finite-dimensional attractors for the Kirchhoff equation with a strong dissipation

The paper studies the existence of the finite-dimensional global attractors and exponential attractors for the dynamical system associated with the Kirchhoff type equation with a strong dissipation utt−M(‖∇u^‖2)Δu−Δut+h(ut)+g(u)=f(x). It proves that the above mentioned dynamical system possesses a global attractor which has finite fractal dimension and an exponential attractor. For application, the fact shows that for the concerned viscoelastic flow the permanent regime (global attractor) can be observed when the excitation starts from any bounded set in phase space, and the dimension of the attractor, that is, the number of degree of freedom of the turbulent phenomenon and thus the level of complexity concerning the flow, is finite.     

Exponential attractors for first-order lattice dynamical systems

In l², we investigate the existence of an exponential attractor for the solution semigroup of a first-order lattice dynamical system acting on a closed bounded positively invariant set which needs not to be compact since l² is infinite dimensional. Up to our knowledge, this is the first time to examine the existence of exponential attractors for lattice dynamical systems.     

Exponential attractor and its fractal dimension for a second order lattice dynamical system

We construct an exponential attractor for a second order lattice dynamical system with nonlinear damping arising from spatial discretization of wave equations in Rk. And we obtain fractal dimension of the exponential attractor and its finite-dimensional approximation.     

On the dimension of the attractor for a perturbed 3d Ladyzhenskaya model

We consider the so-called Ladyzhenskaya model of incompressible fluid, with an additional artificial smoothing term ?Δ³. We establish the global existence, uniqueness, and regularity of solutions. Finally, we show that there exists an exponential attractor, whose dimension we estimate in terms of the relevant physical quantities, independently of ? > 0.     

Uniform exponential attractors for first order non-autonomous lattice dynamical systems

In Abdallah (2008, 2009) [2] and [3], we have investigated the existence of exponential attractors for first and second order autonomous lattice dynamical systems. Within this work, in l², we carefully study the existence of a uniform exponential attractor for the family of processes associated with an abstract family of first order non-autonomous lattice dynamical systems with quasiperiodic symbols acting on a closed bounded set.     

Differentiability of the solution operator and the dimension of the attractor for certain power-law fluids

We study the dynamics of a two-dimensional homogeneous incompressible fluid of power-law type, with the viscosity behaving like (1+|Du|)^p−2, p?2. Here Du is the symmetric velocity gradient. Thanks to the recent regularity results of Kaplický, Málek and Stará, we prove that the solution operator is differentiable. This enables us to use the Lyapunov exponents to estimate the dimension of the exponential attractor. In the Dirichlet setting, the obtained estimates are better than in the case of the Navier-Stokes system.     

A class of continua that are not attractors of any IFS

This paper presents a sufficient condition for a continuum in ? ⁿ to be embeddable in ? ⁿ in such a way that its image is not an attractor of any iterated function system. An example of a continuum in ?² that is not an attractor of any weak iterated function system is also given.     

On non-autonomous strongly damped wave equations with a uniform attractor and some averaging

In this paper we study the existence of a uniform attractor for strongly damped wave equations with a time-dependent driving force. If the time-dependent function is translation compact, then in a certain parameter region, the uniform attractor of the system has a simple structure: it is the closure of all the values of the unique, bounded complete trajectory of the wave equation. And it attracts any bounded set exponentially. At the same time, we consider the strongly damped wave equations with rapidly oscillating external force gε(x,t)=g(x,t,t/ε) having the average g⁰(x,t) as ε→⁰⁺. We prove that the Hausdorff distance between the uniform attractor Aε of the original equation and the uniform attractor A₀ of the averaged equation is less than O(ε1/2). We mention, in particular, that the obtained results can be used to study the usual damped wave equations.     

Convergence of Exponential Attractors for a Finite Element Approximation of the Allen–Cahn Equation

Abstract

We consider a space semidiscretization of the Allen–Cahn equation by continuous piecewise linear finite elements. For every mesh parameter h, we build an exponential attractor of the dynamical system associated with the approximate equations. We prove that, as h tends to 0, this attractor converges for the symmetric Hausdorff distance to an exponential attractor of the dynamical system associated with the Allen–Cahn equation. We also prove that the fractal dimension of the exponential attractor and of the global attractor is bounded by a constant independent of h. Our proof is adapted from the result of Efendiev, Miranville and Zelik concerning the continuity of exponential attractors under perturbation of the underlying semigroup. Here, the perturbation is a space discretization. The case of a time semidiscretization has been analyzed in a previous paper.     

Attractor for the viscous two-component Camassa-Holm equation

This paper is concerned with the attractor for a viscous two-component generalization of the Camassa-Holm equation subject to an external force, where the viscosity term is given by a second order differential operator. The global existence of solution to the viscous two-component Camassa-Holm equation with the periodic boundary condition is studied. We obtain the compact and bounded absorbing set and the existence of the global attractor in H²×H² for the viscous two-component Camassa-Holm equation by uniform prior estimate and many inequalities.     

Hausdorff dimension of attractors for two dimensional Lorenz transformations

A class of transformations on [0, 1]², which includes transformations obtained by a Poincare section of the Lorenz equation, is considered. We prove that the Hausdorff dimension of the attractor of these transformations equalsz+1 wherez is the unique zero of a certain pressure function. Furthermore we prove that all vertical intersections with this attractor, except of countable many, have Hausdorff dimensionz.     

H 4-boundedness of pullback attractor for a 2D non-Newtonian fluid flow

We prove the H4-boundedness of the pullback attractor for a two- dimensional non-autonomous non-Newtonian fluid in bounded domains.     

Asymptotic behaviour of time‐dependent Ginzburg–Landau equations of superconductivity

In this paper, we establish the global fast dynamics for the time‐dependent Ginzburg–Landau equations of superconductivity. We show the squeezing property and the existence of finite‐dimensional exponential attractors for the system. In addition we prove the existence of the global attractor in L² × L² for the Ginzburg–Landau equations in two spatial dimensions. Copyright © 1999 John Wiley & Sons, Ltd.     

Omega-Limit Sets of Generic Points of Partially Hyperbolic Diffeomorphisms

We prove that, for any E^u ⊕ E^cs partially hyperbolic C² diffeomorphism, the ω-limit set of a generic (with respect to the Lebesgue measure) point is a union of unstable leaves. As a corollary, we prove a conjecture made by Ilyashenko in his 2011 paper that the Milnor attractor is a union of unstable leaves. In the paper mentioned above, Ilyashenko reduced the local generecity of the existence of a “thick” Milnor attractor in the class of boundary-preserving diffeomorphisms of the product of the interval and the 2-torus to this conjecture.     

Pullback attractors of non-autonomous micropolar fluid flows

Pullback attractors of the two-dimensional non-autonomous micropolar fluid motion model in a bounded domain are investigated. It is shown that a compact pullback attractor in H¹³(Ω) exists when its external driven function is translation bounded with respect to L₂³(Ω).     

Pullback attractors for the non-autonomous Benjamin-Bona-Mahony equations in H

In this paper, we prove the existence of the pullback attractor for the non-autonomous Benjamin-Bona-Mahony equations in H² by establishing the pullback uniformly asymptotical compactness.     

Uniform attractors for the closed process and applications to the reaction-diffusion equation with dynamical boundary condition

In this paper, we first introduce the concept of a closed process in a Banach space, and we obtain the structure of a uniform attractor of the closed process by constructing a skew product-flow on the extended phase space. Then, the properties of the kernel section of closed process are investigated. Moreover, we prove the existence and structure of the uniform attractor for the reaction-diffusion equation with a dynamical boundary condition in L^p without any restriction on the growth order of the nonlinear term.     

Attractors for semilinear damped wave equations with an acoustic boundary condition

In this paper, we study a semilinear weakly damped wave equation equipped with an acoustic boundary condition. The problem can be considered as a system consisting of the wave equation describing the evolution of an unknown function u = u(x, t), ${x\in\Omega}$ in the domain coupled with an ordinary differential equation for an unknown function δ = δ(x, t), ${x\in\Gamma:=\partial\Omega}$ on the boundary. A compatibility condition is also added due to physical reasons. This problem is inspired on a model originally proposed by Beale and Rosencrans (Bull Am Math Soc 80:1276–1278, 1974). The goal of the paper is to analyze the global asymptotic behavior of the solutions. We prove the existence of an absorbing set and of the global attractor in the energy phase space. Furthermore, the regularity properties of the global attractor are investigated. This is a difficult issue since standard techniques based on the use of fractional operators cannot be exploited. We finally prove the existence of an exponential attractor. The analysis is carried out in dependence of two damping coefficients.     

Random attractors of reaction-diffusion equations with multiplicative noise in L

In this paper, we study the random dynamical system (RDS) generated by the reaction-diffusion equation with multiplicative noise and prove the existence of a random attractor for such RDS in L^p(D) for any p?2.