Experimental Study on Sand/Bed Collision Over the Gobi Surface

The wind-blown sand in the Gobi Desert area significantly influences the occurrence and development of sandstorms. As a key physical process in saltation, sand-bed collisions are significant for wind-blown sand movement. However, till date, there is still a lack of deep understanding and quantitative description of the sand movement in the Gobi, especially for the collision process between sand particles and the surface that has abundant gravel and crust. In this study, the collision process between natural sand particles and the Gobi surface samples, collected in the field, was recorded with a high-speed camera, and the statistical rebound process of particles was reconstructed using a post-processing method. The results show that the collision coefficient of restitution of sand to gravel and crust follows a lognormal distribution and decreases with increasing incident particle speed. Furthermore, the rebound angle also obeys the lognormal distribution, where the incident angle is a critical factor. The bounce property of the sand-bed collision process on the Gobi surface is qualitatively different from that on a loose sand surface. This study provides a new perspective for understanding the splash process and sandstorms on the Gobi surface.