Large-Scale Phenomena. The Conditions of Growth of a Flat Sand Surface

Abstract

IN this chapter we shall deal, as a preliminary to the consideration of real dunes, with the conditions under which sand deposition takes place on a flat surface under a wind of constant direction. Although the areas to be considered are far larger than that of a ripple, and although changes in the wind velocity are involved up to a greater height above the surface, experiments can nevertheless still be carried out on the straight floor of a wind tunnel. But we must remember that the sand on the floor is only the longitudinal section of an imaginary deposition area, and that wind-tunnel experiments can tell us little about the shape of the real area.