Author(s)

P. Siegel, R. Mose & Ph. Ackerer

Abstract

Application of the mixed hybrid finite element approximation in a groundwater flow model: implementation and comparison studies P. Siegel, R. Mose, Ph. Ackerer France ABSTRACT The classical method used in groundwater modelling, the conforming finite element method, calculates first the hydraulic potential field. The velocity field is then obtained by differentiation of this potentiel field. This differentiation leads to a numerical error unacceptable under certain conditions, for example in the presence of heterogeneities or under a large geometric aspect ratio. The solution proposed by the mixed hybrid finite element method is to approximate both the hydraulic potential and the velocity simultaneously and to satisfy an exact water balance for each element. With this method moreover, the normal component of the velocity field is continuous between adjacent elements, which is not the case with the conforming method. The results obtained with the mixed approximation, pre

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