A detailed understanding of small particle deposition process*

The process of dispersion and deposition of particles in wall-bounded turbulent flows is a fundamental issue in many emerging and conventional industries. However, its complexity poses a serious problem which cannot be completely addressed. Therefore, it is important to understand the mechanisms of this phenomenon to help reduce its negative economical and environmental effects. Here, we study particle dispersion and deposition in a fully developed turbulent channel flow at a friction Reynolds number of Re_τ = 180 using the point particle-direct numerical simulation (PP--DNS) method, considering a dilute system. Particulary, we investigate the interplay between particle properties (diameter and density) and deposition dynamics such that different combination of settings lead to the same Stokes number. Additionally, effects of gravity and lift on the deposition process is thoroughly studied.

We aim to demonstrate that the Stokes number alone (the dimensionless particle relaxation time) does not fully capture the deposition dynamics, and the results obtained from zero gravity studies cannot be extrapolated to non-zero gravity settings, even for small particles.