Analysis of sand particles’ lift-off and incident velocities in wind-blown sand flux

Abstract

In the research of windblown sand movement, the lift-off and incident velocities of saltating sand particles play a significant role in bridging the spatial and temporal scales from single sand particle's motion to windblown sand flux. In this paper, we achieved wind tunnel measurements of the movement of sand particles near sand bed through improving the wind tunnel experimental scheme of paticle image velocimetry (PIV) and data processing method. And then the influence of observation height on the probability distributions of lift-off and incident velocities of sand particles was analyzed. The results demonstrate that the observation height has no obvious influence on the distribution pattern of the lift-off and incident velocities of sand particles, i.e., the probability distribution of horizontal and vertical velocities of lift-off and incident sand particles follow a Gaussian distribution and a negative exponential distribution, respectively. However, it influences the center of the Gaussian distribution, the decay constant and the amplitude of the negative exponential distribution.

Laboratory studies of aeolian sediment transport processes on planetary surfaces

“…All together we therefore conclude that the experimental data and the model predictions by Dúran et al 2014 Electrification is seen as a dominant factor in the transport dynamics of dust, affecting the structure, adhesive properties, and detachment/entrainment mechanisms specifically through the formation of aggregates (Merrison et al, 2012). For sand, however, the degree of electrification and the electric fields typically generated (observed) in nature are not intense enough to significantly affect transport rates or thresholds (Rasmussen et al, 2009;Bo et al, 2013). This may not necessarily be the case for extraterrestrial environments.…”

Characterization of Wind‐Blown Sand With Near‐Wall Motions and Turbulence: From Grain‐Scale Distributions to Sediment Transport

“…However, photographic methods is only reliable for the measurement of particles with diameter >0.5 mm (Greeley & Iversen, 1985). Moreover, particle velocity information at low heights (e.g., at <5 mm from the surface) is missing because of relatively high particle concentration (Bo et al., 2013a; Cheng et al., 2006; Dong et al., 2002; Jensen & Sørensen, 1986). Later works updated the instruments used in the wind tunnel experiments.…”

A prediction method for the size distribution of saltating particles above a mixed‐size bed

“…particle-bed collision, the probability distribution of the lift-off velocity and incident velocity of saltating particles was used to characterize the sand movement. Bo et al (2013a) pointed out that the probability distribution of the horizontal lift-off velocities of saltating particles satisfy the Gaussian distribution, but the probability distribution of the vertical velocities of saltating particles was assumed to be a negative exponential distribution. The representations of the vertical and horizontal velocities of the lift-off velocities can reflect the differences of particles sizes (Bo et al, 2013a).…”