Numerical analysis of the influence of the near ground turbulence on the wind-sand flow under the natural wind

摘要

The near-ground turbulent flow of nature air should have an important influence on the wind-sand flow, because of the vegetation and/or micro-topography. However, due to the complexity of turbulent flows, the effects of such turbulences and dust particles are still unknown. In this paper, the large eddy simulation-discrete element method was used to simulate the wind-sand flow. The results show that the response time of the wind-sand flow to turbulence is approximately 1.6 s. In addition, the response time increases rapidly as the particle size increases. The turbulence impact on the sand transport rate first increases and then decreases as the wind velocity fluctuation intensity increases. The sand transport rate is enhanced when the turbulence intensity is less than 0.25, whereas it is weakened when the turbulence intensity exceeds 0.25. Furthermore, the smaller the particle size, the more significant the effect. The effect of turbulence is mainly concentrated at 0.1-0.2 m from the ground and the turbulence increases the height of the wind-sand flow.