Wind-sand flow response law of concave surface upwind plane curve embankment under different wind directions

Understanding the characteristics of wind-sand flow field in the curve section of desert highway under different wind directions is helpful for reducing the wind-sand damage in the curve section. Therefore, taking the desert section of Wuma Expressway in Zhongwei city, Ningxia, China as the research background, the wind-sand flow field and sand accumulation phenomenon of concave surface plane curve embankment under different wind directions is calculated and analyzed by computational fluid dynamics (CFD) numerical simulation method. The results show that: (1) Under different wind directions, along the direction of the route, at the starting point of the route, the windward slope of the embankment is a circular arc section, which reduces the resistance of wind-sand flow and promotes the acceleration of sand particles. In the middle of the route, the low-speed area of the windward slope toe and the leeward slope toe is small; at the end of the route, the high-speed area on the shoulder side of the leeward road rises upward. (2) Under different wind directions, the smaller the angle between the wind direction and the route, the stronger the lateral transport effect on the wind-blown sand flow, and the more sand particles transported along the route direction. (3) Under different wind directions, in the concave windward horizontal curve, with the increase of the angle, the sand area on the top of the embankment shows an increasing trend. When α = 30°, 45°, 60°, 75°, the percentage of the sand area on the top of the embankment to the total embankment area is 0%, 33.3%, 64.4%, 71.0%, respectively. (4) Under different wind directions, along the route direction, the sand transport efficiency of the concave surface upwind plane curve embankment shows a decreasing trend. In the case of a certain radius of the horizontal curve, the angle range between the wind direction and the concave horizontal curve route is recommended to be 30°-45°.