Aerodynamic noise from a high-speed train bogie with complex geometry under a leading car

Among the various aerodynamic noise sources associated with high-speed trains, the bogie regions, and particularly the leading bogie, contribute most to the overall noise. To control this noise, insight into the noise generation mechanisms is imperative but relevant studies are limited due to the difficulties of simulating the flow in regions with complex geometry. An investigation is presented of the aerodynamic noise from a bogie under the leading car of a high-speed train using Delayed Detached Eddy Simulation method. A hybrid grid system is utilized to simulate the flow field, which provides input for the far-field noise calculations based on the Ffowcs Williams and Hawkings equation. Analysis shows that the outer bogie components experience large pressure fluctuations as they are immersed in the shear layer detached from upstream, which is therefore identified as playing a critical role in the noise generation. The resulting noise spectra are broadband and dominated by low frequencies. Compared with the bogie, the bogie cavity and train nose emit 5 dB greater sound power for the current geometry. This study improves understanding of the mechanisms behind the generation of aerodynamic noise in train bogies and lays the foundations for future studies of train bogie noise reduction.