Abstract
Strong wind and sand environments are critical factors affecting high-speed trains' operation. In this paper, the -vortex analysis technique is employed to comparatively analyze the pressure and velocity distribution characteristics of the train surface when the train traveling at a speed of 250km per hour traverses a flat line, a 5m high embankment, and a 3m deep graben in a strong wind and sand environment. Additionally, the study examines the wake turbulence intensity and vortex structural characteristics of the tail car, and the aerodynamic power distribution and sand erosion situation. The results indicate that the change in line type significantly affects the sand flow characteristics around the train, which in turn affects the surface pressure field of the train. When running on the embankment and rift valley lines, more airflow vortices are generated on the leeward side of the train. The foot of the slope also produces a broken vortex structure with high vorticity and strong vortices, which significantly impacts the flow field around the train. In the flat line, the train is subjected to relatively uniform wind and sand impact, but the aerodynamic fluctuations are small; road riffle and embankment, especially on the embankment of the airflow complexity and variability, the flow field structure is the most complex, the aerodynamic characteristics of the train show prominent non-stationary characteristics, the train leeward side of the negative pressure area is also the largest, the transverse force is 45% larger than that in the flat line. In contrast, in the train in the riffle line operation, the headway resistance is significantly reduced. The tail vehicle resistance is the largest, and the drag force suffered is increased, 2.83 times and 0.2 times larger than that on the embankment and flat straight line, respectively.