Impact of key area optimization on the aerodynamic characteristics of a high-speed train in crosswind

To achieve lightweight and high speed, implementing drag reduction measures on trains is of great importance. However, the aerodynamic effects due to such measures can be amplified under crosswind conditions, leading to increased sensitivity in aerodynamic loads. This study investigates the adaptability of different aerodynamic drag reduction strategies for a 400 km/h high-speed train in crosswind using improved delayed detached eddy simulation (IDDES) based on the SST k−ω turbulence model, complemented by wind tunnel validation. Two common strategies (bogie optimization and pantograph optimization), were examined to analyze changes in aerodynamic loads and the surrounding flow evolution. Results indicate that both strategies remain effective in the crosswind, reducing total drag by 66.7% with bogie optimization and by 20.0% with pantograph optimization. Compared to the baseline, bogie optimization significantly enhanced the negative pressure on the leeward side of the leading car, rasing its lateral force by 4.2% and overturning moment by 3.7%, while reducing lift on the middle car by 7.1% and increasing the overturning moment on the tail car by 16.9%. Pantograph optimization slowed leeward vortex development and reduced flow velocity away from the train surface. Additionally, the high negative pressure region on the leeward sides of the middle and tail cars expanded, resulting in a lateral force increase of 39.2% for the middle car and 111.7% for the tail car. Although both optimizations notably reduce aerodynamic drag, they may adversely affect crosswind aerodynamic performance. Within the 100−360 km/h operating range, both optimizations reduce the critical wind speed, substantially affecting the safe operating range. Therefore, when designing drag reduction strategies for high-speed trains, it is essential to consider not only drag reduction performance but also crosswind adaptability to ensure operation safety.