An edge-based finite volume scheme for saturated–unsaturated groundwater flow Original Research Article

The application of a computationally efficient finite volume method for modelling groundwater flow in saturated–unsaturated soils is presented. The flow equation is solved by applying a vertex-centred edge-based finite volume scheme, and the discretisation of the flow domain is achieved using structured and unstructured grids. An acceleration algorithm is employed which utilises an explicit non-linear loop for the primary variable update. The scheme is employed to solve a two-dimensional groundwater flow problem and the results obtained are compared against published solutions. It is shown that the edge-based finite volume scheme captures the saturation front more efficiently than the published finite element solution [Comput. Geosci. 27 (2) (2001) 179]. Moreover, an improvement in the solution is shown by the application of a compact stencil scheme to calculate second-derivative terms as compared to the standard edge-based finite volume scheme.