二维无界区域中不可压非牛顿流体力学方程组的整体吸引子

研究一类二维无界区域中的等热双极不可压粘性非牛顿流体力学方程组，通过证明和相应的解半群的紧性，得到整体吸引子的存在性。     

三维地磁流方程的整体吸引子

在本文中,我们通过引入一类Ｆｒｅｃｈｅｔ空间,得到了三维有界光滑区域上的地磁流方程的弱解的整体吸引子的存在性。     

一类非牛顿流弱解的扰动

主要研究一类可压缩粘性非牛顿流方程弱解的扰动性质.在已知弱解存在的基础上,证明了选取适当范数时,沿着给定的时间序列,密度和速率的扰动趋于零.     

非牛顿粘性不可压流方程的近似惯性流形

本文利用对非牛顿粘性不可压缩流方程对时间 t的解析性和长时间渐近性估计 ,具体构造了它的近似惯性流形 ,并得出收敛阶估计 .     

一类非自治发展方程的一致吸引子

本文研究一类非自治发展方程的渐近行为,运用算子分解及分析技巧得到了系统解的渐近正则性,由此证明一致吸引子的存在性、正则性及其结构.其中非线性项满足临界指数增长,时间依赖的外力项仅假设是平移有界而不是平移紧的.     

拓扑线性空间上算子半群的吸引子

在分离拓扑线性空间上定义了算子半群{V_t}的吸引子,并通过网的概念讨论了极小闭全局吸引子和极小闭全局B-吸引子的关系、临界形式及其存在的充分条件.此外,还讨论了在分离拓扑线性空间上■类算子半群和A■类算子半群的σ-极限集的性质.     

一类非自治时滞抛物方程的一致吸引子

本文研究了一类具有平移有界非自治外力的时滞抛物方程的动力学性态,得到了其整体解的存在和唯一性.利用时间符号理论,并通过构造乘积空间中的紧吸收集,在时间符号空间非紧的情形下得到了一致吸引子的存在性.     

一类非经典扩散方程在强拓扑空间中的指数吸引子

讨论了非经典反应扩散方程ut-△ut-△u=f(u)+g(x)当非线性项满足临界指数增长时,该方程在强拓扑空间H2(Ω)∩H10(Ω)中的指数吸引子的存在性.特别的,通过证明指数吸引子的存在性,可知文献[7,12,14]中的强拓扑空间中的全局吸引子有有限的分形维数.     

一类时滞反应扩散方程的整体吸引子

本文讨论了一类时滞反应扩散方程整体吸引子的存在性,减弱了徐道义6对非线性项满足全局Lipschitz条件的要求,证明了解算子半群在分数幂空间Cα=C(-r,0,Xα)中存在整体吸引子.     

一类广义长短波方程组在无界区域上的整体吸引子

研究了一类广义长短波方程组在无界区域上的解的长时间行为.通过引进加权空间,应用内插不等式和在加权空间的先验估计,证明了长短波方程组整体吸引子的存在性.     

Density-Dependent Incompressible Fluids with Non-Newtonian Viscosity

We study the system of PDEs describing unsteady flows of incompressible fluids with variable density and non-constant viscosity. Indeed, one considers a stress tensor being a nonlinear function of the symmetric velocity gradient, verifying the properties of p-coercivity and (p–1)-growth, for a given parameter p > 1. The existence of Dirichlet weak solutions was obtained in [2], in the cases p 12/5 if d = 3 or p 2 if d = 2, d being the dimension of the domain. In this paper, with help of some new estimates (which lead to point-wise convergence of the velocity gradient), we obtain the existence of space-periodic weak solutions for all p 2. In addition, we obtain regularity properties of weak solutions whenever p 20/9 (if d = 3) or p 2 (if d = 2). Further, some extensions of these results to more general stress tensors or to Dirichlet boundary conditions (with a Newtonian tensor large enough) are obtained.     

A Reproductive Property for a Class of Non-Newtonian Fluids

In this work we analyse a class of non-Newtonian reproductive fluid with a non-linear viscosity. The latter follows the power law or the Carreau's laws which is in common use for polymeric fluids. For a generalized data we introduce some special estimates and then obtain an existence result for the reproductive flow according to certain values of parameters appearing in the model.     

Strong Solutions for Nonhomogeneous Incompressible Viscous Heat-Conductive Fluids with Non-Newtonian Potential

We consider the Navier-Stokes system with non-Newtonian potential for heat-conducting incompressible fluids in a domain Ω R3. The viscosity, heat conduc- tion coefficients and specific heat at constant volume are allowed to depend smoothly on the density and temperature. We prove the existence of unique local strong solu- tions for all initial data satisfying a natural compatibility condition. The difficult of this type model is mainly that the equations are coupled with elliptic, parabolic and hyper- bolic, and the vacuum of density cause also much trouble, that is, the initial density need not be positive and may vanish in an open set.     

Global Existence and Uniqueness of Solution for a Class of Non-Newtonian Fluids

In this paper, we consider a class of non-Newtonian fluids in one-dimensional bounded interval. The global existence and uniqueness of solution are investigated.     

Finite Velocity of the Propagation of Perturbations for a Class of Non-Newtonian Fluids

In this paper, we consider the initial boundary value problem of a class of non-Newtonian fluids. We obtain that finite velocity of the propagation of perturbations.     

一类具有奇异性与真空的非牛顿流局部强解的爆破准则

探讨了如下一类非牛顿流pt+(pu)χ=0,(pu)χ+(pu2)χ-(︱uχ︱p-2uχ)χ+πχ=pf,π=π(p)=Apr,(χ,t)∈Ωr1,A>0,r>1,其初边值条件为(p,u)|t=0=(p0,u0),χ∈(-1,I),u|χ=1=u|χ=-1=0,t∈(0,T1).利用迭代方法,讨论了该模型的局部强解的爆破准则,证明了:如果T_*是强解(ρ,u)存在的最大时间且T*相似文献   

不可压缩非牛顿流体非定常流动初边值问题的非线性半群方法

本文应用非线性半群理论构造了不可压缩非牛顿流体非定常流动初边值问题的强解．     

On Preconditioning of Incompressible Non-Newtonian Flow Problems

This paper deals with fast and reliable numerical solution methods for the incompressible non-Newtonian Navier-Stokes equations. To handle the nonlinearity of the governing equations, the Picard and Newton methods are used to linearize these coupled partial differential equations. For space discretization we use the finite element method and utilize the two-by-two block structure of the matrices in the arising algebraic systems of equations. The Krylov subspace iterative methods are chosen to solve the linearized discrete systems and the development of computationally and numerically efficient preconditioners for the two-by-two block matrices is the main concern in this paper. In non-Newtonian flows, the viscosity is not constant and its variation is an important factor that affects the performance of some already known preconditioning techniques. In this paper we examine the performance of several preconditioners for variable viscosity applications, and improve them further to be robust with respect to variations in viscosity.