Smoothed Particle Hydrodynamics modelling of fresh and salt water dynamics in porous media

Abstract

Abstract Seawater intrusion modelling is often used to assist with groundwater management in coastal areas and islands. Although Smoothed Particle Hydrodynamics (SPH) schemes are able to simulate multi-fluid flows in porous media, they have not been widely tested against experimental observations yet. Additionally, numerical methods for groundwater flow problems need to be able to simulate pumping, which is an unexplored area in SPH. In this study, an Explicit Incompressible SPH (EISPH) solver for multi-fluid flow in porous media is used to simulate the dynamics of freshwater lenses in small islands, and is further developed to simulate groundwater pumping and associated seawater upconing. Three methods to implement a sink term that models water pumping from an aquifer are proposed and compared. The model is successfully tested against data from published laboratory-scale experiments and other numerical models. The results of EISPH are comparable to other models. The inclusion of a sink for water particles to simulate pumping did not affect the stability of the simulations, although one of the three methods led to results that better compared to experimental data. Hence, SPH modelling of groundwater flows in porous media can be successfully achieved using the methods developed here.