Research on drag reduction based on the collaborative arrangement of vortex generators at the head and tail of trains

Vortex generators (VGs) are a form of passive drag reduction technology applied in high-speed trains (HSTs). Considering the bidirectional operational characteristics of trains, a collaborative arrangement of VGs is required at both the head and tail. The effect of collaborative VGs placement at the head and tail is innovatively investigated in this study to optimize drag reduction and flow control. The Reynolds-averaged Navier–Stokes method coupled with the shear stress transport k–ω turbulence model is employed to assess the impact of VG position and design parameters on train aerodynamics. The accuracy of the numerical method has been validated by wind tunnel experiments. It is demonstrated that arranging VGs on the tail vortex separation zone significantly reduces aerodynamic drag. Drag reduction performance improves as the inclination angle decreases, with the optimal angle identified as 15°. At this angle, the tail car drag is reduced by 3.58%, the pressure drag of the entire train decreases by 2.56%, and the overall drag reduction reaches 1.34%. Furthermore, VGs exhibit strong adaptability to varying speeds. Therefore, the collaborative arrangement of VGs at the head and tail effectively reduces aerodynamic drag, offering a promising drag reduction method for the next generation of HSTs.