An Object-oriented computational framework for the simulation of variably saturated flow in soils, using a reduced complexity model

A simple and efficient computational modelling framework is presented for the simulation of variably saturated flows in porous media, which is not based on a conventional numerical solution of the Richards' equation. The computational domain is discretised with a regular grid and simple rules govern the flow dynamics. Each cell can have distinct hydraulic properties and its state depends only on the state of its neighbouring cells. These concepts make the simulation of large-scale variably saturated flow in heterogeneous media easier and computationally more efficient. Due to its object oriented design, the presented framework is very flexible and easily extensible and can be used for various engineering applications (e.g. prediction of rainfall-induced landslides, water and solute transport in agricultural soils), where the simulation of variably saturated flow is crucial. The modelling framework has been validated with experimental results and analytical solutions for 2-D and 3-D problems available from the literature, showing very good agreement even in cases where strong non linearities existed.