Shape Optimization of a Kind of Earth Embankment Type Windbreak Wall along the Lanzhou-Xinjiang Railway

In order to promote the windbreak effect of the earth embankment type windbreak wall, enhance the operational speed of the single passenger train and improve the quality of the pantograph-catenary current collection for a locomotive, a three-dimensional RANS turbulence model k-epsilon was used to optimize the shape of windbreak walls. The relationships between the overturning moment of trains, the lateral wind speed at the catenary position and the height (depth) in optimization projects were analyzed. Validation was performed against full-scale experimental data. To understand the flow field around the train with different types of windbreak walls, pressure contours and surface pressure coefficient distributions were investigated. The results show that for the original type windbreak wall, the overturning moment of the passenger car is a little larger. However, for the optimization projects, the trains are basically in a minor negative pressure environment and the aerodynamic forces are much less. The optimal heights of the heightening type (depths for the cutting type) do not change obviously as the train speed increases. When the passenger car stands on the track without movement, the optimal height/depth is the smallest. Behind the original type's windbreak wall, the lateral wind speed at the catenary position on the leeward line is less than that on the windward line. Meanwhile, as the train runs on the windward or leeward lines, the corresponding lateral wind speed rise sharply by 37.5% and 40.5%, respectively. After the adoption of optimized projects, the speeds of the two lines monotonically decrease. The best height of the heightening type is 0.30 m, and the optimal depth of the cutting type is 1.40 m. From the perspective of engineering application, the heightening type is a more suitable project.