The Effect of Wind Turbulence on the Structure of Streamwise Sand Transport

Abstract

The structure of streamwise sand transport is extremely important in aeolian sand transport research especially near the sand surface because it shall provide guidance for the design of sand‐control engineering. Most of the present theoretic works and numerical simulations on sand sediment and sand flux focus on the research in a one‐dimensional steady logarithmic wind field. Considering the aeolian sand transport as a stochastic process, we calculate trajectories of sand particles responding to vertical turbulent velocity fluctuations. And the effect of the turbulence is obvious on the movement of sand trajectories. The averaged trajectory height with turbulence is higher than that without turbulence which leads to the change of aeolian sand stream structure. The numerical results show that on flat sand the mass flux below 4 cm is about 90% of the total mass flux in the height range of 0–20 cm when turbulence is not included in the simulation, but it will decrease to about 60% when the turbulence is taken into account which is well paralleled with the field experimental data. It is found that turbulence will make the sand especially finer particles fly higher, and the design height of sand‐control engineering should correspondingly include these effects in order to enhance protection efficiency.