Study on the impact of bottom deflector structure on aerodynamic drag reduction characteristics of high-speed trains

WU Zhenfeng; ZHOU Yang; AN Le; LIU Wanlu

doi:10.11860/j.issn.1673-0291.20240047

Abstract：To reduce the aerodynamic drag in the bogie area of high-speed trains,three different bot-tom deflector designs are proposed to efficiently redirect the airflow beneath the train,thereby achiev-ing energy conservation and consumption reduction.Numerical simulations are conducted using the Im-proved Delayed Detached Eddy Simulation(IDDES)method based on the SST k-ω model to compare the aerodynamic drag reduction effects of high-speed trains equipped with different structural deflec-tors.The study also analyzes the impact of these deflectors on the flow field in the bogie area and the wake vortex characteristics.The research results show that,although the total aerodynamic drag of the train body increases after the installation of the deflector,the aerodynamic drag of the bogies is sig-nificantly reduced.The deflector's drainage effect slows the airflow beneath the train,reducing the im-pact of the air on the protruding components of the bogies.The positive pressure area in the bogie area is notably reduced,and the pressure difference between the front and rear of the bogies decreases,which is the main reason for the reduction in the bogies'aerodynamic drag.When the train operates at a speed of 350 km/h,compared with the original model,the aerodynamic drag reduction rates for Model Ⅰ,Model Ⅱ and Model Ⅲ are 8.1%,9.8%and 12.1%,respectively.Furthermore,due to the influence of the deflector,the three-dimensional vortex structures at the rear of the three train mod-els exhibit noticeable changes,and the turbulent kinetic energy near the tail car's nose decreases.This indicates a reduction in the drag effect of the wake vortex on the train,thereby decreasing the overall aerodynamic drag of the high-speed train.