Objective The enclosure condition of undercarriage equipment directly affects the aerodynamic shape of the train, which in turn affects the aerodynamic performance of the whole train. Therefore, it is necessary to carry out a research on the impact of the enclosure condition of undercarriage equipment on the train aerodynamic performance.

Method Taking a certain type of intercity railway train as the baseline model, the wind tunnel and equipment used for aerodynamic testing are elaborated. Two verification model schemes are designed: undercarriage scheme 1 with equipment bay enclosure, and undercarriage scheme 2 without equipment bay enclosure. Aerodynamic force and noise measurement tests are carried out for both schemes. The aerodynamic force test analysis is conducted from three aspects: aerodynamic drag, leading car lift and tail car lift, and crosswind stability; while the aerodynamic noise test comparatively analyzes the differences in far-field aerodynamic noise.

Result & Conclusion  The direct exposure of undercarriage equipment on rail vehicles leads to a significant increase in both overall train drag and tail car lift. Among them, under crosswind-free conditions, the overall train drag increases by 17.4%. Under crosswind conditions, due to the influence of the ground boundary layer, the changes in aerodynamic lift and side force related to crosswind stability are not sensitive. In terms of aerodynamic noise, the exposure of undercarriage equipment has a significant stagnation effect on the incoming flow, reducing the airflow velocity under the train, decreasing the direct impact of the airflow on the bogies and the turbulence intensity in this region, thus resulting in a reduction of sound source intensity. At the two tested speed levels, the average far-field aerodynamic noise decreases by 0.8~1.0 dB(A).