Generation of realistic porous media by grains sedimentation

In a recent paper, Tacher and co-workers proposed an interesting numerical technique to generate granular porous media. Ln this contribution, we prese nt a similar procedure based on a sedimentation algorithm, that is able to overcome some of the difficulties present in the former technique. These ar e: (a) the impossibility to choose a priori a grading curve for the generat ed medium while retaining a realistic stacking where each grain is connecte d to at least three of its neighbours, and, (b) the random pattern of the g rains in the porous medium, arising from their location inside the remainin g void space of a box according to an arbitrary space filling criterion. We propose to generate three-dimensional granular media by simulating the dep osition of spherical grains in a viscous fluid. We argue that the resulting chaotic grain pattern, by reflecting the actual generation process of sedi mentary aggregates more closely, provides a better image of the complex top ology of natural granular porous media. Although the generated medium is ma de up of spheres, it can be transformed, by changing the geometry of the gr ains through suitable domain mappings. The resulting three-dimensional poro us media provide a realistic boundary for the numerical solution of lineari zed Navier-Stokes equations.