Drag model of finite-sized particle in turbulent wall-bound flow over sediment bed

Drag force acting on a particle is vital for the accurate simulation of turbulent multiphase flows, but robust drag model still an open issue. Fully resolved direct numerical (DNS) with immersed boundary method performed to investigate saltating particles in wall turbulence over sediment bed. Results show that, particles, along trajectories cannot be estimated accurately by traditional models originally developed isolated that depends particle-wall separation distance or local volume fraction addition Reynolds number. The errors between and DNS are especially clear during descending phase particles. Through simple theoretical analysis data fitting, we present corrected factor using classical, number dependent as benchmark model. new model, which takes vertical velocity into account, can reasonably predict mean obtained trajectory.