Grain transport rates in steady and unsteady turbulent airflows

摘要: Wind tunnel and field experiments are reported in which continuous, synchronous measurements of grain transport rates near-bed velocity profiles were made at one second intervals to assess mass-flux response variations. Resulting flux series demonstrate the variability concealed by conventional time-averaged data. In steady winds, time-dependent mass found correlate better with fluctuations mean near top saltation layer than estimates instantaneous shear stress. Quasi-periodic oscillation (20–30 seconds) flow lower regions inner boundary is evident such airflows as system moves towards equilibrium a developing bed form confined layer. This phenomenon may not occur nature these time-scales, however.