On the interplay between fluid flow characteristics and small particle deposition in turbulent wall bounded flows.

This article investigates the transport and deposition of small particles (500 nm to 10 μm) in turbulent channel flows at two fluid friction Reynolds numbers (Reτ = 180 and Reτ = 1000) using point particle–direct numerical simulation (PP-DNS) with one-way coupling. The study examines how fluid flow characteristics and gravity influence particle deposition, considering all relevant forces including drag, lift, gravity, and Brownian motion. Results indicate that fluid Reynolds number significantly affects deposition regimes—transitioning from diffusion-dominated to inertia-moderated regimes—and that gravity notably impacts deposition only at low Reynolds numbers, with negligible effects at high Reynolds numbers where particle inertia dominates. The findings emphasize that particle deposition depends on multiple factors beyond the Stokes number, including particle size, density, and flow conditions, which is critical for predicting deposition in industrial and environmental applications.