Preferential concentration by mechanically driven turbulence in the two-fluid formalism

Preferential concentration is thought to play a key role in promoting particle growth, which crucial processes such as warm rain formation clouds, planet formation, and industrial sprays. In this work, we investigate preferential using 3D Direct Numerical Simulations adopting the Eulerian-Eulerian two-fluid approach, where particles are treated continuum field with its own momentum mass conservation laws. We consider Stokes number $St \lesssim O(0.01)$ moderately turbulent flows fluid Reynolds $Re \leq 600$. our previous work (Nasab & Garaud, Physical Review Fluids. doi: 10.1103/PhysRevFluids.5.114308, 2020), established scaling laws predict maximum typical enhancements context of particle-driven convective instability. Here verify that same results apply when turbulence externally driven, extending relevance model wider class particle-laden flows. find particular (i) enhancement above mean scales $u_{rms}^2 \tau_p / \kappa_p$, $u_{rms}$ rms velocity, $\tau_p$ stopping time, $\kappa_p$ assumed diffusivity from equations; (ii) over $(u_{rms}^2 \kappa_p)^{1/2}$; (iii) probability distribution function has an exponential tail whose slope like /\kappa_p)^{-1/2}$. conclude by discussing caveats implications relevant cloud application.