Numerical study on aerodynamic noise reduction of optimized pantograph

The pantograph of a high-speed train, a crucial device for current collection, is a primary source of environmental noise pollution. This study utilized a 1:8 scale model of the CR400BF pantograph, featuring elliptical cross-sections for the panhead and arm frame, and a streamlined bottom frame, operating at a speed of 400 km/h. By combining large eddy simulation with the Ffowcs Williams-Hawkings equation, we investigated the flow field and acoustic characteristics of the pantograph both before and after optimization, focusing on its noise reduction effects and mechanisms. The results show that the optimized pantograph significantly reduces far-field radiated noise, with a maximum noise reduction of 3 dB at the standard measurement point. The droplet-shaped panhead reduces the frontal area and downstream vortices, preventing periodic vortex shedding and significantly decreasing discrete tones noise at 2000 Hz, resulting in a noise reduction of approximately 1.5 dB. The elliptical arms and streamlined bottom frame decrease aerodynamic drag and vortex shedding, thereby weakening the noise source intensity at the rear step surface of the pantograph cavity and the train body surface behind the cavity, leading to a noise reduction of about 1.7 dB. This study demonstrates that aerodynamic acoustic optimization of the pantograph significantly reduces noise in high-speed trains.