Drag and lift characteristics of near-wall multi–particle systems in linear shear flow

This study employs particle–resolved simulations (PRS) based on the immersed boundary method (IBM) to investigate the drag and lift characteristics of multi–particle systems on a solid wall under steady linear shear flow. Two configurations are examined: a single-layer of particles resting directly on the wall, and a double–layer system in which the top–layer particles are influenced by the wall–roughness effect induced by the bottom layer. Simulations cover Reynolds numbers (defined based on the far–field shear rate) of 1, 10, and 100, and surface occupancies (based on the wall-projected particle area) ranging from 0.1 to 0.6. The flow features and the variations in the drag and lift coefficients are analyzed in detail. Finally, empirical correlations for both the drag and lift coefficients are proposed for the single–layer and double–layer configurations.