Equidimensional modelling of flow and transport processes in fractured porous systems I

Abstract

Flow and transport in fractured porous media play an important role for many environmental applications, e.g. the design of disposal systems for hazardous waste. The different hydraulic properties of the fractures and the surrounding rock matrix have a strong influence on the behaviour of the physical processes existing on site. In the two papers of this conference, we will present a new numerical concept to describe saturated flow and transport processes in arbitrarily fractured porous media. We will use an equidimensional approach where fracture and matrix are discretized with elements of the same dimension. To solve the problem, we developed a two-level multigrid method based on a hierarchical decomposition into a fracture problem and a matrix problem. This decoupled treatment of fracture and matrix allows us to handle the locally governing physical processes appropriately. In this paper we will also present convergence comparisons with classical multigrid and algebraic multigrid methods (AMG). In Neunhäuserer et al. (this issue, part II) we will discuss the effect of equidimensionality on the modelling results and the influence of the chosen transport discretisation technique.