Numerical Study on the Effect of Underbody Configurations on the Wake of a High-speed Train

Abstract

The effect of underbody configurations on the wake of a high-speed train (HST) is numerically investigated with improved delayed detached eddy simulation (IDDES). There are two train models which are different in underbody configuration, i.e., complex train with bogie sections and simplified train with flat underbody. Both time-averaged and instantaneous wake structures are compared for the two underbody configurations. For both underbody configurations, a pair of counterrotating streamwise vortices exists in the wake. The vortex pair of the complex train oscillates more violently along the spanwise direction, leading to a wider wake than that of the simplified train. In addition, each of the vortex pair appears alternatively in the wake of the complex train, while the wake of simplified train presents simultaneous coupled vortex pair. The difference in the wake of the two underbody configurations can be attributed to the effect of bogie sections.