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Finite element superconvergence approximation for one‐dimensional singularly perturbed problems
Author(s) -
Zhang Zhimin
Publication year - 2002
Publication title -
numerical methods for partial differential equations
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.901
H-Index - 61
eISSN - 1098-2426
pISSN - 0749-159X
DOI - 10.1002/num.10001
Subject(s) - superconvergence , mathematics , singular perturbation , norm (philosophy) , mathematical analysis , boundary value problem , finite element method , exponential function , logarithm , convection–diffusion equation , perturbation (astronomy) , physics , quantum mechanics , political science , law , thermodynamics
Superconvergence approximations of singularly perturbed two‐point boundary value problems of reaction‐diffusion type and convection‐diffusion type are studied. By applying the standard finite element method of any fixed order p on a modified Shishkin mesh, superconvergence error bounds of ( N −1 ln ( N + 1)) p +1 in a discrete energy norm in approximating problems with the exponential type boundary layers are established. The error bounds are uniformly valid with respect to the singular perturbation parameter. Numerical tests indicate that the error estimates are sharp; in particular, the logarithmic factor is not removable. © 2002 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 18: 374–395, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/num.10001