Two and three dimensional simulation of flow and particle transport in porous media

The simulation of fluid flow and particle transport in porous media finds important applications in many different fields, ranging from environmental and oil engineering to filtration and industrial chromatography. Different types of approaches exist and are generally classified by the length- and time-scales involved. Real industrial problems require the treatment of the porous medium as a continuum via the definition of porosity and permeability. However, these parameters are very difficult to be determined and therefore a strategy to identify them from pore-scale simulation is investigated here. Two and three dimensional geometries characterized by different degrees of complexity are created and studied using finite-element and finite-volume computational fluid dynamics codes. First the flow and particle transport around spherical grains arranged in a regular lattice is investigated. Then the analysis is extended to irregularly arranged spherical grains (of equal and different size) mimicking a realistic porous medium. Eventually geometries constituted by grains of realistic shapes are also considered. The accurate simulation of these systems require the solution of a number of mathematical and numerical challenges, related to computational geometry, mesh pro- cessing and discretization techniques. Particular attention is devoted to the assessment of two meshing strategies: highly irregular body-fitted meshes versus regular cartesian-based immersed-boundary approach.