Flow Kinematics in Three‐Dimensional Porous Media of Varying Pore Size Distribution Using Smoothed Particle Hydrodynamics

The effect of pore size distribution on the flow kinematics and transport properties within a three‐dimensional porous medium is investigated through numerical simulations using the Smoothed Particle Hydrodynamics (SPH) method. The method is first validated for a model porous medium within a monodisperse random spherical packing, for which the velocity distribution of the fluid flowing through the pores (i.e., the interstitial fluid velocity) and the dispersion process are found to be in both qualitative and quantitative agreement with previous experimental results. When varying the pore size distribution of the porous medium by using polydisperse beads (of different diameters), the interstitial fluid velocity distributions get narrower, and the streamlines' tortuosity decreases. This is interpreted as a result of the narrower pore size distribution reported for polydisperse microstructures. Although the dispersion process remains qualitatively the same among the investigated microstructures, with an initial ballistic trend followed by a transient seemingly anomalous regime and eventually a Fickian regime, the transverse dispersion process is found to be quantitatively reduced for polydisperse microstructure (i.e., with a narrower pore size distribution), consistently with the reported decrease in streamlines' tortuosity.