Scaling laws for liftoff velocity for wind-transported particles during
particle-bed collisions
Abstract
We performed wind tunnel studies of sand–bed collisions with natural
sand particles and found an impact angle of 10.5o over a loose bed, and
calculated the critical impact velocity (vic ≅ 1.2027 m s-1). The number
of splashing particles (Ns) increased linearly with vi, but the
coefficient of restitution CoR decreased linearly with vi. The momentum
lost through frictional processes αlost was insensitive to vi, with a
value of 0.2466. The mean splash velocity increased with vi for vi
< 7 m s-1, and gradually reached its maximum value (0.7534 m
s-1) at vi = 7 m s-1, whereas decreased slowly with vi for
vi> 7 m s-1 and gradually approached a constant (0.6137 m
s-1). In addition, we developed a probability distribution model for
liftoff velocity. Our results emphasize the crucial role of the impact
angle and have significant consequences for modeling sand–bed
collisions in a natural environment.