CFD modelling of fluid flow and contaminant transport in hydrogeological systems
This study provides an understanding of various aspects of hydrogeological systems modelling and the use of computational techniques to predict and optimise hydrological parameter assessment, anisotropic scaling, macrodispersion and solute flux measurements under unsteady, uniform/non-uniform flow conditions. The incorporated models are structured around multi-physics continuum mechanics analysis to investigate fluid flow and solute transport in hydrogeological systems. The control-volume unstructured mesh configuration, based on cell-centred or vertex-based FV algorithms for CFD and CSM problems is employed. The non-linear material behaviour exhibited by porous soils and the fluid flow evaluation under system stresses is described by elasto-visco-plastic constitutive relationships and the coupling between CFD and CSM processes. The designed simulation models are used to calibrate the flow problems associated with regional groundwater levels estimation, determination of soil hydraulic properties and moisture distribution in dry soils in response to infiltration of compressible or incompressible fluids. For solute transport problems, investigations of spatial distribution of solute species in homogeneous/layered heterogeneous systems are undertaken by accounting for chemical, geochemical and biological reactions caused by particle deposition processes and liquid-solid interactions in natural subsurface systems. The simulated shape and spread of contaminant plume are effectively influenced by the governing transport mechanism for solutes. The attention in leachate is predicted to have a significant role in reducing the level of contaminant concentration and its potential impact on the attainable groundwater resources.