A uniformly convergent difference scheme for a semilinear singular perturbation problem

Summary We present a difference scheme for solving a semilinear singular perturbation problem with any number of turning points of arbitrary orders. It is shown that a solution of the scheme converges, uniformly in a perturbation parameter, to that of the continuous problem.     

High order generalized upwind schemes and numerical solution of singular perturbation problems

High even order generalizations of the traditional upwind method are introduced to solve second order ODE-BVPs without recasting the problem as a first order system. Both theoretical analysis and numerical comparison with central difference schemes of the same order show that these new methods may avoid typical oscillations and achieve high accuracy. Singular perturbation problems are taken into account to emphasize the main features of the proposed methods. AMS subject classification (2000)  65L10, 65L12, 65L50     

A UNIFORM NUMERICAL METHOD FOR QUASILINEAR SINGULAR PERTURBATION PROBLEM WITH A TURNING POINT

A nonlinear difference scheme is given for solving a quasilinear siagularly perturbed two-point boundary value problem with a turning point. The method uses non-equidistant discretization meshes. The solution of the scheme is shown to be first order accurate in the discrete L^∞ norm, uniformly in the perturbation parameter.     

An equation decomposition method for the numerical solution of a fourth‐order elliptic singular perturbation problem

In this article, we propose a tailored finite point method (TFPM) for the numerical solution of a type of fourth‐order singular perturbation problem in two dimensions based on the equation decomposition technique. Our finite point method has been tailored based on the local exponential basis functions. Furthermore, our TFPM satisfies the discrete maximum principle automatically. Our numerical examples show that our method has second order convergence rate in energy norm as $\varepsilon\to0$ . © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2011     

A second-order difference scheme for a parameterized singular perturbation problem

In this paper we consider a singularly perturbed quasilinear boundary value problem depending on a parameter. The problem is discretized using a hybrid difference scheme on Shishkin-type meshes. We show that the scheme is second-order convergent, in the discrete maximum norm, independent of singular perturbation parameter. Numerical experiments support these theoretical results.     

Uniform fourth order difference scheme for a singular perturbation problem

Summary The numerical solution of a nonlinear singularly perturbed two-point boundary value problem is studied. The developed method is based on Hermitian approximation of the second derivative on special discretization mesh. Numerical examples which demonstrate the effectiveness of the method are presented.This research was partly supported by NSF and SIZ for Science of SAP Vojvodina through funds made available to the U.S.-Yugoslav Joint Board on Scientific and Technological Cooperation (grants JF 544, JF 799)     

On the non-existence of -uniform finite difference methods on uniform meshes for semilinear two-point boundary value problems

In this paper fitted finite difference methods on a uniform mesh with internodal spacing , are considered for a singularly perturbed semilinear two-point boundary value problem. It is proved that a scheme of this type with a frozen fitting factor cannot converge -uniformly in the maximum norm to the solution of the differential equation as the mesh spacing goes to zero. Numerical experiments are presented which show that the same result is true for a number of schemes with variable fitting factors.

     

A singular perturbation problem with discontinuous data in a cuboid

We analyse the asymptotic behaviour of the solution of a 3Dsingularly perturbed convection–diffusion problem withdiscontinuous Dirichlet boundary data defined in a cuboid. Wewrite the solution in terms of a double series and we obtainan asymptotic approximation of the solution when the singularparameter 0. This approximation is given in terms of a finitecombination of products of error functions and characterizesthe effect of the discontinuities on the small -behaviour ofthe solution in the singular layers.     

An iterative method based on equation decomposition for the fourth‐order singular perturbation problem

In this article, we propose an iterative method based on the equation decomposition technique ( 1 ) for the numerical solution of a singular perturbation problem of fourth‐order elliptic equation. At each step of the given method, we only need to solve a boundary value problem of second‐order elliptic equation and a second‐order singular perturbation problem. We prove that our approximate solution converges to the exact solution when the domain is a disc. Our numerical examples show the efficiency and accuracy of our method. Our iterative method works very well for singular perturbation problems, that is, the case of 0 < ε ? 1, and the convergence rate is very fast. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013     

High order finite volume methods for singular perturbation problems

In this paper we establish a high order finite volume method for the fourth order singular perturbation problems.In conjunction with the optimal meshes,the numerical solutions resulting from the method have optimal convergence order.Numerical experiments are presented to verify our theoretical estimates.     

奇异非线性二阶微分方程Neumann边值问题

研究了一个奇异非线性二阶微分方程的Neumann边值问题,通过摄动技巧和比较原理得到了所论问题解的存在唯一性。     

Sharp by order estimates of solutions of a simplest singular boundary value problem

We consider a boundary value problem ((0.1)) where f ∈ L_p (?), p ∈ [1, ∞] (L∞ (?) ? C (?)) and 0 ≤ q ∈ L^loc₁ (?). For a given p ∈ [1, ∞], for a correctly solvable problem (0.1) in L_p (?), we obtain minimal requirements to a positive, continuous function Θ(x) for x ∈ ? under which, regardless of f ∈ L_p (?), the solution y ∈ L_p (?) of problem (0.1) satisfies the equality . (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Orderh 2 method for a singular two-point boundary value problem

A method is described based on auniform mesh for the singular two-point boundary value problem:y+(/x)y+f(x, y)=0, 0<x1,y(0)=0,y(1)=A, and it is shown to be orderh ² convergent forall 1.     

An almost fourth order uniformly convergent difference scheme for a semilinear singularly perturbed reaction-diffusion problem

Summary. This paper is concerned with a high order convergent discretization for the semilinear reaction-diffusion problem: , for , subject to , where . We assume that on , which guarantees uniqueness of a solution to the problem. Asymptotic properties of this solution are discussed. We consider a polynomial-based three-point difference scheme on a simple piecewise equidistant mesh of Shishkin type. Existence and local uniqueness of a solution to the scheme are analysed. We prove that the scheme is almost fourth order accurate in the discrete maximum norm, uniformly in the perturbation parameter . We present numerical results in support of this result. Received February 25, 1994     

Graded Galerkin methods for the high‐order convection‐diffusion problem

We develop a Galerkin method using the Hermite spline on an admissible graded mesh for solving the high‐order singular perturbation problem of the convection‐diffusion type. We identify a special function class to which the solution of the convection‐diffusion problem belongs and characterize the approximation order of the Hermite spline for such a function class. The approximation order is then used to establish the optimal order of uniform convergence for the Galerkin method. Numerical results are presented to confirm the theoretical estimate.© 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009     

Uniform convergence analysis of finite difference approximations for singular perturbation problems on an adapted grid

A singularly perturbed two-point boundary value problem with an exponential boundary layer is solved numerically by using an adaptive grid method. The mesh is constructed adaptively by equidistributing a monitor function based on the arc-length of the approximated solutions. A first-order rate of convergence, independent of the perturbation parameter, is established by using the theory of the discrete Green's function. Unlike some previous analysis for the fully discretized approach, the present problem does not require the conservative form of the underlying boundary value problem. Dedicated to Dr. Charles A. Micchelli for his 60th birthday Mathematics subject classifications (2000) 65L10, 65L12. This work is supported by National Science Foundation of China, the key project of China State Education Ministry and Hunan Education Commission.     

一类非共振奇异半正边值问题正解的存在性

研究了一类二阶导数项系数β<π~2的非共振奇异半正四阶边值问题,得到了其C~2[0,1]∩C~4(0,1)正解存在的一个判定方法,进一步改进和推广了有关文献的结果.     

A second‐order immersed interface technique for an elliptic Neumann problem

A second‐order finite difference scheme for mixed boundary value problems is presented. This scheme does not require the tangential derivative of the Neumann datum. It is designed for applications in which the Neumann condition is available only in discretized form. The second‐order convergence of the scheme is proven and the theory is validated by numerical examples. © 2006 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 23: 400–420, 2007     

Solutions for a class of singular nonlinear boundary value problem involving critical exponent

In this paper, we consider the existence of multiple solutions for a class of singular nonlinear boundary value problem involving critical exponent in Weighted Sobolev Spaces. The existence of two solutions is established by using the Ekeland Variational Principle. Meanwhile, the uniqueness of positive solution for the same problem is also obtained under different assumptions.