**Numerical investigation of particle velocity distributions in aeolian sand transport**

Liqiang Kang^{ a,b,}*, Dayou Liu ^{c}

a State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China

b MOE Engineering Research Center of Desertifi cation and Blown-sand Control, Beijing Normal University, Beijing 100875, China

c Center for Plasma and Combustion Research, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China

**Abstract**

Particle velocity distribution in a blowing sand cloud is a reflection of saltation movement of many particles. Numerical analysis is performed for particle velocity distribution with a discrete particle model. The probability distributions of resultant particle velocity in the impact–entrainment process, particle horizontal and vertical velocities at different heights and the vertical velocity of ascending particles are analyzed. The probability distributions of resultant impact and lift-off velocities of saltating particles can be expressed by a log-normal function, and that of impact angle comply with an exponential function. The probability dis-tribution of particle horizontal and vertical velocities at different heights shows a typical single-peak pattern. In the lower part of saltation layer, the particle horizontal velocity distribution is positively skewed. Further analysis shows that the probability density function of the vertical velocity of ascending particles is similar to the right-hand part of a normal distribution function, and a general equation is acquired for the probability density function of non-dimensional vertical velocity of ascending particles which is independent of diameter of saltating particles, wind strength and height. These distributions in the present numerical analysis are consistent with reported experimental results. The present investigation is important for understanding the saltation state in wind-blown sand movement.

**Published in ***Geomorphology* 115 (2010) 156–171