Discussions of Some Issues for Wind Blown Sand Flow Simulation

The transport of dust and sand by wind can provide a major mechanism conducive to land form changes due to aeolian activity, including sandy coasts, deserts and agricultural fields. Meanwhile, a strong electric field and electrical discharge phenomena could exist and be associated with the generation of dust storms. The wind-blown sand blown flow is a kind of gas-solid two-phase flow. Nowadays, numerical modeling methods are usually employed by researchers for its convenience and speed in forecasting and assessments on pollutants dispersions and variations. Generally, a CFD-DEM method is used for wind-blown sand blown flow simulation, in which large eddy simulation (LES) is a method of computational fluid dynamics (CFD) to simulate the dynamic flow of gas or air and discrete element method (DEM) is often used to simulate the particle-particle collision. Giving the initial and boundary conditions is the key to get the appropriate simulation results. In this study, some issues for wind blown sand flow simulations are discussed, 1) the effect of time-series inlet wind velocity attributed to the atmospheric boundary layer movements that induced by regional climate and local meteorological process; 2) the role of water content adsorbed on sand surface for the tribo-electric charging of wind-blown sand; 3) the evaluation of the inter-particle contact time and contact area in the real heat transfer process when the softening treatment used in the DEM method to track the movement of each particle.