Large-scale clustering of inertial particles in homogeneous isotropic turbulence

International audienceThe nonlinear dynamics of inertial particles in high Reynolds number turbulence, and in particular clustering and void formation, are important fundamental processes, for instance, for droplets in atmospheric clouds and rain formation. Here we analyze particle data from three-dimensional direct numerical simulations of particle-laden homogeneous isotropic turbulence at high Reynolds number, up to Re_λ = 678 and with up to 3.2 × 10 9 particles, computed at resolution 4096^3. We show that the particle density spectrum of the analyzed data has a bump at large scales for sufficiently high Reynolds number, in addition to the near-dissipation scale bump observed so far. The large-scale bump is attributed to large-scale clustering of inertial particles. We find that this behavior is generic and independent of the forcing scheme used to maintain a statistically stationary flow