Role of shear-induced lift force in the spatial distribution of resuspended particles

The Eulerian-Lagrangian point-particle model is coupled with direct numerical simulation of a wall-bounded turbulent flow to study the spatial distribution of particles resuspended from a fractal-like multiscale rough surface. A dynamical stochastic resuspension model is employed to model the process of particle resuspension on the surface. Particular attention is paid to the effect of shear-induced Saffman lift force. The computation results demonstrate that the shear-induced lift force can play a significant role in spatial particle distribution and particle statistics near the wall, e.g., the preferential accumulation, as well as local streaky clustering of particles near the wall, is remarkably weakened for all particles by including the shear-induced lift force. By analyzing the correlation between particle motion and flow structures, it is found that the centrifuging and turbophoresis effects are degraded by the lift force. A formal relation for particle number density distribution from the kinetic equation of the probability density function of particle position and velocity is extended to quantitatively elucidate the mechanism that leads to the different distributions of particles in the wall turbulent flow, especially the spanwise inhomogeneity of particle distribution.