Key Takeaways & Executive Findings
- •• Scale effects in pantograph cavity coupling systems significantly influence aerodynamic noise generation, with smaller scales reducing overall radiated sound pressure levels. • The dominant sound generation mechanism transitions from pure tone noise at larger scales to broadband noise at smaller scales due to turbulent boundary layer masking. • A novel scale correction model combining sound source energy and dimensionless spectrum corrections enables accurate mapping of reduced-scale noise results to full-scale predictions. • The findings provide critical insights for developing precision noise control technologies for high-speed trains.
Abstract
The pantograph cavity coupling system (PCCS) of high-speed trains, as a representative region for aerodynamic noise generation, merits further investigation into its scale effects. In this paper, the large-eddy simulation (LES) and the Ffowcs Williams-Hawkings (FW-H) integral equation are used to calculate and analyze the sound energy intensity distribution pattern and spectral characteristics of the PCCS at different scales (1/1, 1/2, 1/4, 1/8, 1/16, 1/25, 1/50). The research shows that as the scaled model decreases, the relative area of the pantograph submerged by the vehicle boundary layer increases, and its inflow velocity decreases, thereby reducing the overall radiated sound pressure level in this area. For the segments 1/1−1/2 and 1/4−1/16, the dominant scale of sound generation is typical pure tone noise, with distinct similar features in the spectral discrete scales. For the segments 1/25−1/50, the turbulent fluctuation characteristics of the vehicle boundary layer mask the peak features, and the spectrum is dominated by broadband characteristics. Combining the PCCS sound source energy scale correction model and the dimensionless spectrum correction function, a scale correction model for the sound power spectrum of the sound source is obtained, so that the noise results of the reduced-scale model can be corresponded to the full-scale model. This work advances the comprehension of high-speed train aerodynamic noise generation mechanisms and offers critical references for developing precision noise control technologies.
1. Introduction
The pantograph cavity coupling system (PCCS) is one of the main sources of noise during high-speed train operation [1, 2]. Therefore, the PCCS noise control has become an important and unavoidable topic in the development of high-speed trains [3]. However, due to the limitations of the acoustic wind tunnel size and the calculation scale and accuracy, existing studies usually avoid full-scale model studies and use scaled vehicle models for research [4, 5].
BAKER [6] showed that the aerodynamic drag results of the reduced-scale model can be extrapolated to obtain full-scale results. The research results of HAN et al [7] show that under different operating conditions (trains on open track, passing each other on open track, through a tunnel and passing each other in tunnel), scaled model has a certain impact on aerodynamic coefficients and surface pressure distributions. THOMPSON et al [8] drew on the noise source prediction model for landing gear from the field of aeronautical acoustics [9], and proposed a component-based approach to modelling the aerodynamic noise from the pantograph area. QIN et al [10] used pipelines to connect the front and rear edges of the cavity to disrupt the shear layer oscillations and achieve the aerodynamic drag reduction and noise reduction effects in the cavity. OKAJIMA [11] used experimental methods to investigate the relationship between Strouhal and Reynolds numbers for rectangular columns with different aspect ratios. QIN et al [12] proposed a method for separating and quantifying pantograph dipole and quadrupole noise, showing that at different operating speeds of a high-speed train, the distribution of the two aerodynamic noise sources does not change, but the intensity increases significantly. LIU et al [13] investigated the drag reduction effect of the covering structure on the pantograph. The study showed that the covering structure reduced the total drag of a three-car train by 5.6%. SUN et al [14] analyzed the influence of the train formation, the position, number and configuration of pantographs on the flow field and wake vortices around high-speed trains. YU et al [15] calculated the near-field and far-field sound fields around the pantograph system. The results show that the nois...
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TAN Xiao-ming, FU Bao-jun, CHEN Zheng-wei, LIU Jia-ming, WU Yu-cai, YANG Zhi-gang, HUANG Sha (2025). Radiated noise correction model for the dominant scale correlation of aerodynamic sound generation in pantograph cavity coupling system. Journal of Central South University. https://doi.org/10.1007/s11771-025-6146-5
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Frequently Asked Questions
What is the pantograph cavity coupling system (PCCS) and why is it important?
The PCCS is a key noise source in high-speed trains, formed by the pantograph and its surrounding cavity. Understanding its aerodynamic noise generation is crucial for developing noise control technologies.
How does scale affect aerodynamic noise in the PCCS?
As the scale decreases, the relative area of the pantograph submerged by the vehicle boundary layer increases, reducing inflow velocity and overall radiated sound pressure. The dominant noise mechanism shifts from pure tone to broadband as scale decreases.
What methods were used in this study?
The study employed large-eddy simulation (LES) and the Ffowcs Williams-Hawkings (FW-H) integral equation to compute sound energy distribution and spectral characteristics at various scales.
What is the main contribution of this paper?
The paper proposes a scale correction model that combines sound source energy and dimensionless spectrum corrections, enabling accurate mapping of reduced-scale noise results to full-scale predictions.
What are the practical implications of this research?
The findings provide critical references for developing precision noise control technologies for high-speed trains, potentially leading to quieter and more efficient designs.
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