Superconvergence of conforming finite element for fourth-order singularly perturbed problems of reaction diffusion type in 1D

2013 ◽  
Vol 30 (2) ◽  
pp. 550-566 ◽  
Author(s):  
Hailong Guo ◽  
Can Huang ◽  
Zhimin Zhang
2017 ◽  
Vol 17 (2) ◽  
pp. 337-349 ◽  
Author(s):  
Christos Xenophontos

AbstractWe consider fourth order singularly perturbed problems in one-dimension and the approximation of their solution by the h version of the finite element method. In particular, we use piecewise Hermite polynomials of degree ${p\geq 3}$ defined on an exponentially graded mesh. We show that the method converges uniformly, with respect to the singular perturbation parameter, at the optimal rate when the error is measured in both the energy norm and a stronger, ‘balanced’ norm. Finally, we illustrate our theoretical findings through numerical computations, including a comparison with another scheme from the literature.


2015 ◽  
Vol 15 (2) ◽  
pp. 135-143 ◽  
Author(s):  
Philippos Constantinou ◽  
Christos Xenophontos

AbstractWe present the mathematical analysis for the convergence of an h version Finite Element Method (FEM) with piecewise polynomials of degree p ≥ 1, defined on an exponentially graded mesh. The analysis is presented for a singularly perturbed reaction-diffusion and a convection-diffusion equation in one dimension. We prove convergence of optimal order and independent of the singular perturbation parameter, when the error is measured in the natural energy norm associated with each problem. Numerical results comparing the exponential mesh with the Bakhvalov–Shishkin mesh from the literature are also presented.


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