scholarly journals Analysis of Aerodynamic Noise Characteristics of High-Speed Train Pantograph with Different Installation Bases

2019 ◽  
Vol 9 (11) ◽  
pp. 2332 ◽  
Author(s):  
Yongfang Yao ◽  
Zhenxu Sun ◽  
Guowei Yang ◽  
Wen Liu ◽  
Prasert Prapamonthon
Keyword(s):  
High Speed ◽  
Near Field ◽  
Complex Structure ◽  
Aerodynamic Noise ◽  
High Speed Train ◽  
Noise Sources ◽  
Eddy Simulation ◽  
Noise Characteristics ◽  
Large Eddy ◽  
Flow Phenomena

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.

Aerodynamic Noise Reduction Analysis in High-Speed Train Cab

2014 ◽  
Vol 1049-1050 ◽  
pp. 1022-1025
Author(s):  
Xiao Feng Zhang ◽  
You Gang Xiao ◽  
Liang Sun ◽  
Yu Shi
Keyword(s):  
High Speed ◽  
Power Flow ◽  
Simulation Method ◽  
Aerodynamic Noise ◽  
High Speed Train ◽  
Interior Decoration ◽  
Eddy Simulation ◽  
Head Surface ◽  
Large Eddy ◽  
Fluctuation Pressure

In order to reduce aerodynamic noise in high-speed train cab,the SEA model of cab is established. The fluctuation pressures from train head surface are calculated by large eddy simulation method. Using fluctuation pressure as excitation force, power flow caused by airflow among sub-systems of SEA model of cab is obtained. Two schemes are put forward to reduce the aerodynamic noise in cab, namely interior decoration modification and windowpane thickness increase. The results show that when a layer of splint with 0.01 m thickness, 0.5 loss factor is added to the original decoration in cab, the overall sound pressure level (SPL) at driver head location will reduce 1.23 dB(A). When the cab windowpane thickness is increased to 5 mm from 4 mm, the overall SPL at the driver head location will reduce 0.87 dB(A).

Shape Optimization of High-Speed Train Pantograph Insulators for Low Aerodynamic Noise

2012 ◽  
Vol 249-250 ◽  
pp. 646-651
Author(s):  
Xiao Yan Yang ◽  
You Gang Xiao ◽  
Yu Shi
Keyword(s):  
Shape Optimization ◽  
Sound Pressure Level ◽  
High Speed ◽  
Sound Pressure ◽  
Pressure Level ◽  
Aerodynamic Noise ◽  
High Speed Train ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Elliptical Section

With large eddy simulation(LES) and Lighthill-Curle acoustic theory, the aerodynamic noises radiated from pantograph insulators with rectangular, circular, elliptical section were calculated, and the optimal pantograph insulator shape was obtained. The results show that in the same model, the sound pressure level (SPL) spectrum at different monitoring points are basically the same, but the amplitude is different. In different models, the SPL spectrum are different. As for rectangular, circular, elliptical section insulators, the frequency with maximum SPL reduces gradually. For reducing aerodynamic noise, the elliptical section insulator is optimal, and the long elliptical axis should be consistent with air flow. The pantograph with bigger and less components is helpful to reduce the aerodynamic noise.

scholarly journals Source Contribution Analysis for Exterior Noise of a High-Speed Train: Experiments and Simulations

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Jie Zhang ◽  
Xinbiao Xiao ◽  
Dewei Wang ◽  
Yan Yang ◽  
Jing Fan
Keyword(s):  
High Speed ◽  
Noise Source ◽  
High Speed Train ◽  
Noise Sources ◽  
Sound Sources ◽  
Lower Region ◽  
Source Contribution ◽  
Array Measurements ◽  
Noise Characteristics ◽  
Train Speed

This paper presents a detailed investigation into the contributions of different sound sources to the exterior noise of a high-speed train both experimentally and by simulations. The in situ exterior noise measurements of the high-speed train, including pass-by noise and noise source identification, are carried out on a viaduct. Pass-by noise characteristics, noise source localizations, noise source contributions of different regions, and noise source vertical distributions are considered in the data analysis, and it is shown how they are affected by the train speed. An exterior noise simulation model of the high-speed train is established based on the method of ray acoustics, and the inputs come from the array measurements. The predicted results are generally in good agreement with the measurements. The results show that for the high-speed train investigated in this paper, the sources with the highest levels are located at bogie and pantograph regions. The contributions of the noise sources in the carbody region on the pass-by noise increase with an increasing distance, while those in the bogie and train head decrease. The source contribution rates of the bogie and the lower region decrease with increasing train speed, while those of the coach centre increase. At a distance of 25 m, the effect of the different sound sources control on the pass-by noise is analysed, namely, the lower region, bogie, coach centre, roof region, and pantograph. This study can provide a basis for exterior noise control of high-speed trains.

scholarly journals Research on Aerodynamic Noise Reduction for High-Speed Trains

2016 ◽  
Vol 2016 ◽  
pp. 1-21 ◽  
Author(s):  
Yadong Zhang ◽  
Jiye Zhang ◽  
Tian Li ◽  
Liang Zhang ◽  
Weihua Zhang
Keyword(s):  
Noise Reduction ◽  
High Speed ◽  
Low Noise ◽  
Broadband Noise ◽  
Full Scale ◽  
Noise Model ◽  
Aerodynamic Noise ◽  
High Speed Train ◽  
Detached Eddy Simulation ◽  
Noise Sources

A broadband noise source model based on Lighthill’s acoustic theory was used to perform numerical simulations of the aerodynamic noise sources for a high-speed train. The near-field unsteady flow around a high-speed train was analysed based on a delayed detached-eddy simulation (DDES) using the finite volume method with high-order difference schemes. The far-field aerodynamic noise from a high-speed train was predicted using a computational fluid dynamics (CFD)/Ffowcs Williams-Hawkings (FW-H) acoustic analogy. An analysis of noise reduction methods based on the main noise sources was performed. An aerodynamic noise model for a full-scale high-speed train, including three coaches with six bogies, two inter-coach spacings, two windscreen wipers, and two pantographs, was established. Several low-noise design improvements for the high-speed train were identified, based primarily on the main noise sources; these improvements included the choice of the knuckle-downstream or knuckle-upstream pantograph orientation as well as different pantograph fairing structures, pantograph fairing installation positions, pantograph lifting configurations, inter-coach spacings, and bogie skirt boards. Based on the analysis, we designed a low-noise structure for a full-scale high-speed train with an average sound pressure level (SPL) 3.2 dB(A) lower than that of the original train. Thus, the noise reduction design goal was achieved. In addition, the accuracy of the aerodynamic noise calculation method was demonstrated via experimental wind tunnel tests.

Multi-field coupling prediction for improving aeroacoustic performance of muffler based on LES and FW-H acoustic analogy methods

2021 ◽  
pp. 1475472X2110054
Author(s):  
H Guo ◽  
YS Wang ◽  
F Zhu ◽  
NN Liu ◽  
C Yang
Keyword(s):  
High Speed ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Aerodynamic Noise ◽  
Acoustic Analogy ◽  
Field Coupling ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Fillet Transition ◽  
Experimental Validations

Based on the large eddy simulation (LES) and Ffowcs Williams and Hawkings (FW-H) equation, a multi-field coupling method is presented for aeroacoustic prediction of a muffler with high-speed and high-temperature exhaust gasflow. A three-dimensional finite-volume model of the muffler is established by using the LES and FW-H acoustic analogy (FW-H-AA) methods. Experimental validations of the simulated results suggest a good accuracy of the combined LES and FW-H-AA approach. Some factors influencing on noise attenuation, such as the gasflow velocity, temperature and the structural parameters of the muffler are analyzed. The results show that the aerodynamic noise and turbulent kinetic energy (TKE) are mainly attributed to the structural mutations in the muffler. The outlet sound pressure level (SPL) increases with the inlet gasflow velocity and decreases with temperature. According to the factor analysis results, the target muffler is modified by adding a fillet transition to the end of inserted tube and redesigning the structures where the TKE concentrated for improving the aerodynamic performance. In terms of the outlet SPL, the inner TKE and the backpressure of the muffler, the modified muffler is significantly improved by the maximum reductions of 3-5dB in SPL, 10–20% in TKE and 0.5–2.5 kPa in backpressure. The presented method might be extended to other kinds of muffler for aeroacoustic calculation and improvement design.

Aerodynamic noise characteristics of high-speed train foremost bogie section

2020 ◽  
Vol 27 (6) ◽  
pp. 1802-1813
Author(s):  
Xi-feng Liang ◽  
Hui-fang Liu ◽  
Tian-yun Dong ◽  
Zhi-gang Yang ◽  
Xiao-ming Tan
Keyword(s):  
High Speed ◽  
Aerodynamic Noise ◽  
High Speed Train ◽  
Noise Characteristics

scholarly journals Aerodynamic noise radiating from the inter-coach windshield region of a high-speed train

2018 ◽  
Vol 37 (3) ◽  
pp. 590-610 ◽  
Author(s):  
Wen-Qiang Dai ◽  
Xu Zheng ◽  
Zhi-Yong Hao ◽  
Yi Qiu ◽  
Heng Li ◽  
...  
Keyword(s):  
Sound Pressure Level ◽  
High Speed ◽  
Sound Pressure ◽  
Near Field ◽  
Acoustic Power ◽  
Pressure Level ◽  
Aerodynamic Noise ◽  
Dominant Factor ◽  
High Speed Train ◽  
Frequency Range

The aerodynamic noise has been the dominant factor of noise issues in high-speed train as the traveling speed increases. The inter-coach windshield region is considered as one of the main aerodynamic noise sources; however, the corresponding characteristics have not been well investigated. In this paper, a hybrid method is adopted to study the aerodynamic noise around the windshield region. The effectiveness of simulation methods is validated by a simple case of cavity noise. After that, the Reynolds-averaged Navier–Stokes simulation is used to obtain the characteristics of flow field around the windshield region, which determine the aerodynamic noise. Then the nonlinear acoustic solver approach is employed to acquire the near-field noise, while the Ffowcs-Williams/Hawking equation is solved for far-field acoustic propagation. The results indicate that the windshield region is approximately an open cavity filled with severe disturbance flow. According to the analysis of sound pressure distribution in the near-acoustic field, both sides of the windshield region appear symmetrical two-lobe shape with different directivities. The results of frequency spectrum analysis indicate that the aerodynamic noise inside inter-coach space is a typical broadband one from 100 Hz to 5k Hz, and most acoustic power is restricted in the low-medium frequency range (below 500 Hz). In addition, the acoustic power in the low frequency range (below 100 Hz) is closely related to the cavity resonance with the resonance peak frequency of 42 Hz. The overall sound pressure level at different speeds shows that the acoustic power grows approximately 5th power of the train speed. Two forms of outside-windshields are designed to reduce the noise around the windshield region, and the results show the full-windshield form is better in noise reduction, which apparently eliminates interior cavity noise of inter-coach space and lessens the overall sound pressure level on the sides of near-field by about 13 dB.

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