Effects of Covering Layer of Sand Particles on Particle-Bed Collision and Aeolian Sand Transport

摘要

The movement of sand particles on the desert is the primary mechanism resulting in the development of sandstorms. Scientists have found that the physicochemical environments of terrestrial planets can cause the surface of sand particles to form a peelable covering layer, which may shed gradually during the movement of sand particles and affect the collision process between sand particles and bed surface, and finally affect aeolian sand transport itself. However, only a few studies have investigated these microscopic physical processes and conducted quantitative analysis of the relationship between covering layer mass and its coefficient of restitution (COR) when a particle impact desert surface. In this study, we collected four types of natural sand particles from the Badain Jaran, Mu Us, and Taklimakan deserts and the shoreside of the Yellow River respectively. A hydrochloric acid solution was used to dissolve the surface-covering layer of sand particles, and high-speed photography was used to capture the process of particle-bed collision. The motion characteristics of the sand particles under different covering layers were analyzed using statistical analysis, and the quantitative formula between the COR and the covering layer mass was provided. This calculation result was further incorporated into an aeolian sand transport model to evaluate the effect of the covering layer on sand flux. Considering the ubiquity of covering layer on sand particle, the methodology proposed in this study can be used to simulate sand drift on Earth, Mars, and other terrestrial planets more accurately.