Effect of simplifying bogie regions on aerodynamic performance of high-speed train

An investigation of the effect of simplifying bogie regions on the aerodynamic performance of a high-speed train was carried out by studying four train models, to explore possible ways to optimise the train underbody structure, improve the underbody aerodynamic performance, and reduce the aerodynamic drag. The shear stress transport (SST) k-omega turbulence model was used to study the airflow features of the high-speed train with different bogie regions at Re=2.25x10(6). The calculated aerodynamic drag and surface pressure were compared with the experimental benchmark of wind tunnel tests. The results show that the SST k-omega model presents high accuracy in predicting the flow fields around the train, and the numerical results closely agree with the experimental data. Compared with the train with simplified bogies, the aerodynamic drag of the train with a smooth surface and the train with enclosed bogie cavities/inter-carriage gaps decreases by 38.2% and 30.3%, respectively, while it increases by 10.8% for the train with cavities but no bogies. Thus, enclosing bogie cavities shows a good capability of aerodynamic drag reduction for a new generation of high-speed trains.