Accumulated densities of sedimenting particles in turbulent flows
Sozza, Alessandro; Drotos, Gabor; Hernandez-Garcia, Emilio; Lopez, Cristobal
We study the effect of turbulence on a sedimenting layer of particles by means of direct numerical simulations. A Lagrangian model in which particles are considered as tracers with a downward settling velocity is integrated together with an isotropic homogeneous turbulent flow. We study the spatial distribution of particles when they are collected on a plane at non-asymptotic times. We relate the resulting coarse-grained particle density to the history of the stretching rate along the particle trajectory and its projection onto the accumulation plane, and analyse the degree of clustering and the deviation from homogeneity in terms of the Reynolds number and the settling velocity.