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Numerical investigation of the impact of wall boundaries on aerodynamic noise in high-speed trains
(2026-01-01)
Ma, Zhi Yuan
;
Feng, Qing Song
;
Prapamonthon, Prasert
;
Cheng, Gong
;
Sun, Zhen Xu
As the operating speed of high-speed trains continues to rise, aerodynamic noise has become a critical factor influencing train performance and passenger comfort, especially in confined environments like tunnels. In this study, a comprehensive simulation of the aerodynamic noise generated during the entire ‘open air-tunnel-open air’ transition at 450 km/h was performed using the improved delayed detached eddy simulation (IDDES) turbulence model and overset grid method, with results validated against field measurements. The findings reveal that, compared to open-air conditions, the tunnel environment induces higher-flow velocities around the train, stronger pressure fluctuations on the train surface, and more pronounced vortex shedding in the wake. Sound pressure levels (SPLs) at surface measurement points are typically about 10 dB(A) higher in the tunnel, with the primary differences observed in the 100–300 Hz frequency range, while both scenarios exhibit spectral peaks near 530 Hz. In the bogie region, tunnel noise is dominated by pressure-wave coupling and wall reflections, which amplify low- and mid-frequency components, whereas under open-air conditions, local vortex shedding and wake instabilities prevail, resulting in more high-frequency noise. The web structure contributes to the reduction of aerodynamic noise from the bogie area, with a particularly significant decrease observed in tunnel conditions. Along the tunnel wall, the SPL initially increases and then decreases, reaching a peak of 125.7 dB(A). After exiting the tunnel, the measurement points at Section L in the open air show a reduction of approximately 10 dB(A) compared to the corresponding tunnel-wall points. This study highlights the substantial amplification of low-frequency noise caused by wall confinement and demonstrates the noise-reduction potential of the web structure. The results provide valuable theoretical insights and numerical evidence for aerodynamic noise control in higher-speed train tunnels, offering significant engineering implications.
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Aerodynamic optimization using passive control devices near the bogie cabin of high-speed trains
(2022-09-01)
Yao, Yongfang
;
Sun, Zhenxu
;
Li, Guibo
;
Yang, Guowei
;
Prapamonthon, Prasert
Bogies are responsible for a significant amount of aerodynamic resistance and noise, both of which negatively affect high-speed train performance and passenger comfort. In the present study, the passive control method is applied in designing the bogie cabins of a high-speed train to improve its aerodynamic characteristics. Two passive control measures are introduced, namely, adding a spoiler and creating diversion grooves near the bogie cabins. Furthermore, the aerodynamic and aeroacoustic characteristics of a high-speed train operating at 350 km/h under different control strategies are numerically investigated using the improved-delayed-detached-eddy simulation (IDDES) and the acoustic finite element method (FEM). The impacts of passive control devices on drag reduction, slipstream, and aerodynamic noise are presented and discussed. Numerical results reveal that the passive control devices have a major effect on the slipstream around the train. The amplitude of the fluctuating pressure is higher in the first half of the train than in the second half. The first bogie has the maximum amplitude of the acoustic pressure for both the train with and without passive devices. In the far field, the spoiler installation and placement of the diversion grooves in the front of the bogie cabin can significantly reduce aerodynamic drag and noise. Hence, as shown in this study, using passive control methods to improve the aerodynamic and aeroacoustic properties of high-speed trains can be a viable option. [Figure not available: see fulltext.].
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Numerical Investigation on Aerodynamic Drag and Noise of Pantographs with Modified Structures
(2022-01-01)
Yao, Y.
;
Sun, Z.
;
Li, G.
;
Prapamonthon, P.
;
Cheng, G.
It is well known that the pantograph, which works as a complex component of high-speed trains, is an important source of aerodynamic drag and aerodynamic noise of a high-speed train (HST) that can affect HST performance, comfort for passengers, and quietness of nearby communities. Thus, comprehensive studies on aerodynamic characteristics including aerodynamic drag and aerodynamic noise obtained by the pantograph need to be conducted. This work presents the aerodynamic characteristics including aerodynamic resistance and aerodynamic noise generated by the prototype pantograph of a high-speed train running at a speed of 300 km/h using numerical techniques of improved delayed detached-eddy simulation (IDDES) and acoustic finite element method (FEM). Then, the structure of the original pantograph is modified by wrapping the insulators, and the base frame, so that aerodynamic resistance and aerodynamic noise may be reduced as expected. Numerical results obtained from the pantograph without modification, with two modifications to the original design i.e. the base frame, and the insulators, are discussed. Compared to the original pantograph, the two modifications of the pantograph at the base frame and the support insulators are conducive to reducing the aerodynamic drag of the pantograph. However, the results also show that the modified insulator may not achieve considerable success in noise reduction. Only the modified base frame shows that noise is reduced significantly. Therefore, this suggests that the pantograph with base frame modification is a better choice for resistance and noise reduction.
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Analysis of aerodynamic noise characteristics of high-speed train pantograph with different installation bases
(2019-06-01)
Yao, Yongfang
;
Sun, Zhenxu
;
Yang, Guowei
;
Liu, Wen
;
Prapamonthon, Prasert
The high-speed-train pantograph is a complex structure that consists of different rod-shaped and rectangular surfaces. Flow phenomena around the pantograph are complicated and can cause a large proportion of aerodynamic noise, which is one of the main aerodynamic noise sources of a high-speed train. Therefore, better understanding of aerodynamic noise characteristics is needed. In this study, the large eddy simulation (LES) coupled with the acoustic finite element method (FEM) is applied to analyze aerodynamic noise characteristics of a high-speed train with a pantograph installed on different configurations of the roof base, i.e. flush and sunken surfaces. Numerical results are presented in terms of acoustic pressure spectra and distributions of aerodynamic noise in near-field and far-field regions under up- and down-pantograph as well as flushed and sunken pantograph base conditions. The results show that the pantograph with the sunken base configuration provides better aerodynamic noise performances when compared to that with the flush base configuration. The noise induced by the down-pantograph is higher than that by the up-pantograph under the same condition under the pantograph shape and opening direction selected in this paper. The results also indicate that, in general, the directivity of the noise induced by the down-pantograph with sunken base configuration is slighter than that with the flush configuration. However, for the up-pantograph, the directivity is close to each other in Y-Z or X-Z plane whether it is under flush or sunken roof base condition. However, the sunken installation is still conducive to the noise environment on both sides of the track.

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