Experimental Study of Blown Sand in a Vegetated Area

Wind-tunnel experiments were conducted to investigate the effects of vegetation, in particular beach grass, on blown sand in terms of elevation changes of a mobile sand bed and distributions of mean wind velocity for various vegetation canopies. For flexible vegetation layer displacement amplitude of vegetation leaf sway was also measured. The results indicate that a vegetation canopy with low height, high density, and vegetation flexibility is effective in reducing the sand-transport rate. Within and above a canopy of flexible vegetation, the vibrations of leaves increases the air turbulence, which creates a complex interaction between the mean wind velocity and the air turbulence, and thereby reduces the wind velocity in the vegetation area; consequently, the sand-transport rate decreases.