Digital image analysis on motion parameters of saltating sand grains

A high-speed digital camera was adopted to record the saltation of sand grains in an atmospheric boundary layer (ABL) wind tunnel. The bidirectional particle tracking algorithm was employed in matching interframe particles and abstracting trajectories from image sequence. The time based curve fitting and the derivation were applied to calculate motion parameters for the position function of sand particle saltation. Compared with conventional and frequency reduced discrete difference methods, the present curve fitting and continuous derivation method is more effective in single-particle continuous motion analysis. Moreover, the drag acceleration and the way of the general lift force in wind direction are achieved.