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

Based on 3D,steady N-S equations and k-ε 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.

Based on 3D, steady N-S equations and k-e 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 fiat 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.