Clustering of Inertial Particles in Turbulent Flow Through a Face-Centered Cubic Cell

Fine inertial particle migration, transport and deposition is of importance in several applications such as hyporheic exchange of river beds, gravel packs in enhanced oil recovery, among others. Specifically, how turbulence within confined geometries of a porous bed affects migration, clustering, and deposition of fine particles is of importance. Direct numerical simulation is performed to investigate effect of turbulent flow in a face centered cubic porous unit cell on the transport of inertial particles at different Stokes numbers ($St_p = 0.01, 0.1, 0.5, 1$, and $2$) and at a pore Reynolds number of 500. Particles are advanced using one-way coupling and collision of particles with pore walls is modeled as perfectly elastic specular reflection. The pattern of clustering is investigated using multiscale wavelet analysis and area of Voronoi tessellation cells. The results are compared with preferential concentration in forced isotropic turbulence to investigate the effect of geometric confinement on particle clustering. It is shown that the general features of cluster and void formation and higher order statistics of number density of particles are modified by the wall collision creating very fine scale clusters.