Aims and scopeThe journal provides English translations of selected new, original Russian papers on the theoretical aspects of numerical analysis and the application of mathematical methods to simulation and modelling. The editorial board, consisting of the most prominent Russian scientists in numerical analysis and mathematical modelling, select papers on the basis of their high scientific standard, innovative approach and topical interest.Papers are published in the following areas:
Numerical analysis• Abstract -The first boundary value problem for a singularly perturbed parabolic PDE with convection is considered on un interval. For the case of sufficiently smooth data, it is easy to construct a standard finite difference operator and a piecewise uniform mesh condensing in the boundary layer, which gives an e-uniformly convergent difference scheme. The order of convergence for such a scheme is exactly one and close to one up to a small logarithmic factor with respect to the time and space variables, respectively. In this paper we construct high-order time-accurate E-uniformly convergent schemes by a defect-correction technique. The efficiency of the new defect-correction scheme is confirmed by numerical experiments.We consider the first boundary value problem for a singularly perturbed parabolic PDE with convection on an interval. The highest derivative in the equation is mul· tiplied by an arbitrarily small parameter E. When the parameter E tends to zero, boundary layers may appear, which leads to difficulties when classical discretization methods are applied, because the error in the approximate solution depends on the value of E. The appropriate location of the nodes is needed to ensure that the er· ror is independent of the parameter value and depends only on the number of nodes in the mesh. Special schemes with this property are called E-uniformly convergent.In [1][2][3][4][5] we introduced and analysed E-uniformly convergent difference schemes for singularly perturbed boundary value problems for elliptic and parabolic equations.If the problem data is sufficiently smooth, for the parabolic equations with convec· tion terms, the order of E-uniform convergence for the scheme studied is exactly one and up to a small logarithmic factor one with respect to the time and space variables, respectively, i.e. O(N-1 In 2 N +K-1 ), where N and K are the number of intervals in the space and time discretization. Because the amount of the computational work is proportional to the number K, the higher-order accuracy in time can considerably reduce the computational cost. Therefore it is of interest to develop methods for which the order of convergence with respect to the time variable is increased. For equations without convective terms the improvement of the accuracy in time, preserving E·uniform convergence, by means of a defect-correction technique was also studied in [ 4,5). In this paper we develop schemes for which the order of *cwr,