© 2003 by Institute of Mathematics and its Applications
Convergence of a finite-volume mixed finite-element method for an elliptichyperbolic system
1 Département de Mathématiques, CC 051, Université de Montpellier II, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France 2 Université de Marne-la-Vallée, Marne-la-vallée Cedex 2, 77454, France 3 laboratoire de Mathematiques, CNRS et Université Paris-Sud, 91405, Orsay Cedex, France
This paper gives a proof of convergence for the approximate solution of an elliptichyperbolic system, describing the conservation of two immiscible incompressible phases flowing in a porous medium. The approximate solution is obtained by a mixed finite-element method on a large class of meshes for the elliptic equation and a finite-volume method for the hyperbolic equation. Since the considered meshes are not necessarily structured, the proof uses a weak total variation inequality, which cannot yield a BV-estimate. We thus prove, under an L
estimate, the weak convergence of the finite-volume approximation. The strong convergence proof is then sketched under regularity assumptions which ensure that the flux is Lipschitz continuous.
Key Words: finite-volume method; mixed finite-element method; system of a hyperbolic and an elliptic equation
Received 6 February 2002. Revised 30 September 2002.