Navier－Stokes方程稳定性研究（Ⅱ）

本文对Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程与热传导方程的性质进行了比较。法国数学家、偏微分方程权威Ｊ．Ｌｅｒａｙ教授在其对Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程的研究中，曾由热传导方程出发而求得Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程某种初（边）值问题的适定性结果￣［２］．巴黎十一大学的Ｒ．Ｔｅｍａｍ等专家、教授也曾多次提出过将两类方程类比的疑问。本文试将其中根本不同点做了叙述和例证。     

关于第一类广义Navier—Stoke方程的不稳定性

本文应用分层理论,证明了第一类广义Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程是一类不稳定方程。     

Navier－Stokes方程稳定性研究（Ⅰ）

本文给出Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程某种边值问题局部解不唯一性的一个例证。     

Navier—Stokes方程组的一个一致有效渐近解

本文利用多重尺度法研究了大雷诺数情况下的平板绕流问题，得到了Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程的一个一致有效渐近解。     

Navier—Stokes方程稳定性研究

本给出Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程某种边值问题局部解不唯一性的一个例证。     

广义Navier－Stokes方程的整体解（Ⅰ）、（Ⅱ）

该文讨论了（Ⅰ）、（Ⅱ）两类广义Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程，通过一系列精确的估计，得到了其广义解的整体存在性．     

粘流—无粘干扰流动理论变分问题迭代序列的收敛性和算子方程…

本文证明了粘流－无粘干扰流动理论基本控制方程－简化的Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程变分问题几种迭代序列的收敛性，并探讨了其算子方程的性质。本文的结论对于简化Ｎ－Ｓ方程的数值计算具有指导意义。     

二维N－S方程的Fourier非线性Galerkin方法

本文对周期边界条件Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程，证明了其Ｆｏｕｒｉｅｒ非线性Ｇａｌｅｒｋｉｎ逼近解的存在唯一性，同时给出了逼近解的误差估计．     

二维全空间上线性阻尼Navier-Stokes方程的全局吸引子及其维数估计

本文研究二维全空间上线性阻尼Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程的大时间性态央餐力项ｆ（ｘ）∈（Ｌ＾２（Ｒ＾２）＾２而不需要对ｆ（ｘ）作任何加权限制的条件下,证明了线性阻尼Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程的全局吸引子的存在性,并给出了其Ｈａｕｓｄｏｒｆｆ及Ｆｒａｃｔａｌ维数估计。     

Navier—Stokes方程的稳态解和吸引子

本文将证明Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程的解当ｔ→＋∞时趋于稳态解，并由此推出Ｎ－Ｓ方程存在集合满足泛吸引子或函数不变集条件的充要条件。     

Oseen Coupling Method for the Exterior Flow Part I: Oseen Coupling Approximation

Abstract In this paper, we consider the bidimensional exterior unsteady Navier-Stokes equations with nonhomogeneous boundary conditions and present an Oseen coupling problem which approximates the Navier-Stokes problem, obtained by coupling the Navier-Stokes equations in the inner region and the Oseen equations in the outer region. Moreover, we prove the existence, uniqueness and the approximate accuracy of the weak solution of the Oseen coupling equations. Project supported by NSF of China & State Major Key Project of Basic Research     

Oseen coupling method for the exterior flow. Part II: Well‐posedness analysis

In this paper, we recall the Oseen coupling method for solving the exterior unsteady Navier–Stokes equations with the non‐homogeneous boundary conditions. Moreover, we derive the coupling variational formulation of the Oseen coupling problem by using of the integral representations of the solution of the Oseen equations at an infinity domain. Finally, we provide some properties of the integral operators over the artificial boundary and the well‐posedness of the coupling variational formulation. Copyright © 2004 John Wiley & Sons, Ltd.     

FINITE ELEMENT NONLINEAR GALERKIN COUPLING METHOD FOR THE EXTERIOR STEADY NAVIER-STOKES PROBLEM

1.IntroductionNonlinearGalerkinmethodsaremultilevelschemesforthedissipativeevolutionpartialdifferentialequations.Theycorrespondtothesplittingsoftheunknownu:u=y z)wherethecomponentsareofdifferentorderofmagnitudewithrespecttoaparameterrelatedtothespati...     

A Non-Conforming Least Squares Spectral Element Formulation for Oseen Equations with Applications to Navier-Stokes Equations

In this article, we propose a non-conforming exponentially accurate least-squares spectral element method for Oseen equations in primitive variable formulation that is applicable to both two- and three-dimensional domains. First-order reformulation is avoided, and the condition number is controlled by a suitable preconditioner for velocity components and pressure variable. A preconditioned conjugate gradient method is used to obtain the solution. Navier-Stokes equations in primitive variable formulation have been solved by solving a sequence of Oseen type iterations. For numerical test cases, similar order convergence has been achieved for all Reynolds number cases at the cost of higher iteration number for higher Reynolds number.     

Generalized Darcy–Oseen resolvent problem

In this paper, we study the well‐posedness of a coupled Darcy–Oseen resolvent problem, describing the fluid flow between free‐fluid domains and porous media separated by a semipermeable membrane. The influence of osmotic effects, induced by the presence of a semipermeable membrane, on the flow velocity is reflected in the transmission conditions on the surface between the free‐fluid domain and the porous medium. To prove the existence of a weak solution of the generalized Darcy–Oseen resolvent system, we consider two auxiliary problems: a mixed Navier–Dirichlet problem for the generalized Oseen resolvent system and Robin problem for an elliptic equation related to the general Darcy equations. © 2016 The Authors Mathematical Methods in the Applied Sciences Published by John Wiley & Sons Ltd.     

First‐order system least squares for the Oseen equations

Following earlier work for Stokes equations, a least squares functional is developed for two‐ and three‐dimensional Oseen equations. By introducing a velocity flux variable and associated curl and trace equations, ellipticity is established in an appropriate product norm. The form of Oseen equations examined here is obtained by linearizing the incompressible Navier–Stokes equations. An algorithm is presented for approximately solving steady‐state, incompressible Navier–Stokes equations with a nested iteration‐Newton‐FOSLS‐AMG iterative scheme, which involves solving a sequence of Oseen equations. Some numerical results for Kovasznay flow are provided. Copyright © 2006 John Wiley & Sons, Ltd.     

Solutions of the Stokes,Oseen, and Navier-Stokes Equations in Three Dimensions

A constructive analytical procedure is described for generating a class of solutions pertaining to the fluid velocity field satisfying the three-dimensional Navier-Stokes equations. The arbitrary functions occurring in the solution are related to those that arise in the general solution of the Stokes and Oseen equations.     

Shape optimization of a body in the Oseen flow

This article is concerned with a numerical simulation of shape optimization of the Oseen flow around a solid body. The shape gradient for shape optimization problem in a viscous incompressible flow is computed by the velocity method. The flow is governed by the Oseen equations with mixed boundary conditions containing the pressure. The structure of continuous shape gradient of the cost functional is derived by using the differentiability of a minimax formulation involving a Lagrange functional with a function space parametrization technique. A gradient type algorithm is applied to the shape optimization problem. Numerical examples show that our theory is useful for practical purpose and the proposed algorithm is feasible. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010     

A numerical method for the viscous incompressible Oseen flow in shape reconstruction

This paper is concerned with the shape reconstruction of a bounded domain with a viscous incompressible fluid driven by the Oseen equations. For the approximate solution of the ill-posed and nonlinear problem we propose a regularized Gauss-Newton method. A theoretical foundation for the method is given by establishing the differentiability of the boundary value problem with respect to the boundary in the sense of the domain derivative. The results of several numerical experiments show that our theory is useful for practical purpose, and the proposed algorithm is feasible.     

A new defect correction method for the Navier-Stokes equations at high Reynolds numbers

In this paper, a new defect correction method for the Navier-Stokes equations is presented. With solving an artificial viscosity stabilized nonlinear problem in the defect step, and correcting the residual by linearized equations in the correction step for a few steps, this combination is particularly efficient for the Navier-Stokes equations at high Reynolds numbers. In both the defect and correction steps, we use the Oseen iterative scheme to solve the discrete nonlinear equations. Furthermore, the stability and convergence of this new method are deduced, which are better than that of the classical ones. Finally, some numerical experiments are performed to verify the theoretical predictions and show the efficiency of the new combination.