Lateral aerodynamic performance and speed limits of double-deck container vehicles with different structures

Abstract

Based on 3D, steady N-S equations and k-ɛ turbulence model, Fluent was employed to do numerical simulation for lateral aerodynamic performance of 6-axis X2K double-deck container trains with two different loading forms, and speed limits of the freight trains were studied. The result indicates that under wind environment: 1) As for vehicles without and with cross-loaded structure, aero-pressure on the former is bigger, but air velocity around the latter is larger; 2) When sideslip angle θ=0°, the airflow is symmetry about train vertical axis; when θ>0°, the airflow is detached at the top of vehicles, and the air velocity increases above the separated line but decreases below it; 3) With θ increasing, the lateral force on the mid vehicle firstly increases but decreases as θ=75°; 4) When the 6-axis X2K flat car loads empty boxes of a 40 ft and a 48 ft at 120 km/h, the overturning wind speed is 25.19 m/s, and the train should be stopped under the 12th grade wind speed.