WIND TUNNEL TEST STUDY ON COMPLEX WIND FIELD AND VEHICLE AERODYNAMIC EFFECTS IN EMBANKMENT-CUTTING TRANSITION ZONE IN HIGH-SPEED RAILWAY

The topography and geomorphology are complex and changeable in China, and the railway transition zones are indispensable. In order to investigate the vehicle aerodynamic effects and complex wind field in embankment-cutting transition zone, a large-scale model was established to measure the wind speed profiles above the track and the train aerodynamic forces at different locations along the track by using wind tunnel test. The test results show that the influence height of embankment-cutting transition zone on air flow is less than 250 mm above the track. The wind velocity profile at the lower height of the railway junction is dominated by the cutting while the higher height is dominated by the embankment. Wind speed has little influence on the changing trend of train aerodynamic forces along the track. In the transition zone, the most unfavorable area for traffic safety exists near the junction of the railway, especially at the sides of embankment. The aerodynamic coefficients decrease while the wind speed increases due to the Reynolds number effect.