Investigation on aerodynamic characteristics of high-speed trains with shields beneath bogies

Abstract

The key issue for developing energy-saving high-speed trains is to optimize aerodynamic performance. Therefore, the strategy of installing shields beneath bogies (SBBs) is proposed to improve the aerodynamic performance of the train further. A high-speed train Case0 without SBB and two high-speed trains Case1 and Case2 with different SBBs are established. Numerical simulations are carried out using the IDDES method to analyze the differences in the aerodynamic characteristics of the three trains. According to the findings, the largest error in surface pressure between the wind tunnel test and numerical simulation is roughly 3.6%. The aerodynamic resistance of the head, middle, and tail car of Case1 is reduced by 29.7%, 7.3%, and −7.2% in comparison to Case0, respectively, and that of Case2 train is reduced by 56.7%, 32.1%, and 17.1%. The aerodynamic resistance of the whole Case1 and Case2 is reduced by 12.2% and 37.7%, respectively, with Case2 having a more significant drag reduction effect. The vortex shedding range of Case0 is approximately 1.35 times that of Case2. Moreover, the presence and type of the SBB will affect the flow field around and behind Bogie6, resulting in a 9° difference in the wake downwash angle between Case2 and Case0. A comprehensive analysis of the surface pressure and aerodynamic forces of the train, the pressure, velocity, turbulence kinetic energy, and vortex structure of the flow field reveals that Case 2 exhibits lower aerodynamic resistance and better characteristics in the flow field. The study's findings can serve as data support and reference for the research and development of next-generation high-speed trains and installing equipment on railways.