A random pairing collision model (RPCM) for improving the DEM simulation of particle-bed collisions in aeolian sand transport

The impact of sand particles with bed is the key process in aeolian sand transport. In this article, the discrete element method (DEM) is embedded to the large-eddy simulation (LES) method for simulating the wind-blown sand two-phase flow. A numerical model is developed to stochastically describe collisions between sand particles and bed within the DEM approach. Statistical features of major simulated motion parameters are undertaken and compared with measured data to verify the model. The probability distribution of the kinetic energy restitution coefficient is normal, and the probability density functions of the impact and lift-off angles are consistent with reported results. The probability density functions of three-dimensional impact and lift-off velocities are addressed in further detail.