Abstract: In order to further explore the characteristics of sand transport during the initiation process of aeolian sand transport, the developing process of initiation of aeolian sand transport was measured by PTV (particle tracking velocimetry) technology in a wind tunnel. The variation of particle space distribution, the horizontal particle velocity, sand transport rate, particle number density and sand flux with time is analyzed. The result shows that the time consumption is about 1.5 s for the initiation process of aeolian sand transport. During the initiation process, the sand transport rate increases rapidly with time, the total particle number in air increases exponentially with time, and the variation of both particle number density and sand flux with height can be approximately expressed by a negative exponential function. At the same height, the mean horizontal particle velocity at t=1.0 s is larger than that after this time, the particle number density after t=1.5 s is larger than that at t=0.5 s and 1.0 s, and the sand flux after t=1.5 s is more than that at t=1.0 s. The decay rate of particle number density with height generally decreases with time, and approximates to a constant after t=1.5 s.

Key words: aeolian sand transport, initiation, wind tunnel experiment