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DIFFERENtIAl & DIFFERENCE EqUAtIONS ANd APPlICAtIONS

DIFFERENtIAl & DIFFERENCE EqUAtIONS ANd APPlICAtIONS

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AN H 1 -GALERKIN MIXED FINITE ELEMENT METHOD<br />

FOR LINEAR AND NONLINEAR PARABOLIC PROBLEMS<br />

NEELA NATARAJ AND AMBIT KUMAR PANY<br />

An H 1 -Galerkin mixed finite element method is proposed to approximate the solution<br />

as well as flux of one-dimensional linear and nonlinear parabolic initial boundary value<br />

problems. Error estimates have been given and the results of numerical experiments for<br />

two examples have been shown.<br />

Copyright © 2006 N. Nataraj and A. K. Pany. This is an open access article distributed<br />

under the Creative Commons Attribution License, which permits unrestricted use, distribution,<br />

and reproduction in any medium, provided the original work is properly cited.<br />

1. Introduction<br />

In [9], an H 1 -Galerkin mixed finite element method is proposed to solve linear parabolic<br />

problems. Contrary to the standard H 1 -Galerkin finite element method [6, 10], the C 1 -<br />

continuity condition in the definition of the finite element spaces for approximating the<br />

solution has been relaxed in this method.<br />

The standard mixed finite element procedure demands the satisfaction of the LBB<br />

condition by the approximating finite element subspaces. This restricts the choice of the<br />

finite element spaces for approximating u and its flux. This bottle neck has been overcome<br />

in this method and the approximating finite element spaces V h and W h are allowed to be<br />

of different polynomial degrees. Also, the quasiuniformity condition on the finite element<br />

mesh need not be imposed in this method.<br />

In this paper, first of all, an implementation of the H 1 -Galerkin mixed finite element<br />

method [9] which gives a simultaneous approximation to the solution as well as its flux<br />

for linear parabolic problems has been done. Secondly, an interesting application of this<br />

mixed method for approximating the solution and flux of Burgers’ equation has been<br />

described. The unknown and its derivative are approximated simultaneously using globally<br />

continuous piecewise linear elements in the discrete level. Error estimate results have<br />

been stated and results of some numerical experiments are presented.<br />

Burgers’ equation, being a simplified form of Navier-Stokes equation and also due<br />

to its immense physical applications, has attracted researcher’s attention since the past<br />

few decades. Numerical methods like finite difference, finite element, as well as spectral<br />

Hindawi Publishing Corporation<br />

Proceedings of the Conference on Differential & Difference Equations and Applications, pp. 851–860

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