Numerical Analysis of Aerodynamic Noise of a New High-Speed Train

2013 ◽  
Vol 275-277 ◽  
pp. 681-686 ◽  
Author(s):  
Wei Chen ◽  
Song Ping Wu
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Body Surface ◽  
High Speed ◽  
Source Model ◽  
Broadband Noise ◽  
Physical Models ◽  
Aerodynamic Noise ◽  
High Speed Train ◽  
Car Body

Along with the raising of the train speed, aerodynamic noise of the high-speed train is generated more and more significantly and their reduction has become one of the key factors to control noise of the high-speed train. Aerodynamic noise radiated from the high-speed train surface was analyzed numerically. The mathematical and physical models of the three dimensional flow field of the high-speed train were established and the external steady and unsteady flow fields of the high-speed train were calculated by using the standard "k-ε" turbulence model and large eddy simulation (LES) respectively. On the basis of the steady flow field, aerodynamic noise sources on the car body surface of the high-speed train are calculated by using the broadband noise source model. On the basis of the unsteady flow field, the time domain characteristics of fluctuating pressures on the car body surface are analyzed. The sound pressure level on the surface pressure demonstrating is calculated and the flow field of some critical parts is analyzed.

Numerical Analysis of the Surface Aerodynamic Noise of the CRH3 High Speed Train

2014 ◽  
Vol 1044-1045 ◽  
pp. 643-649
Author(s):  
Ji Zhou Liu ◽  
Ren Xian Li ◽  
Peng Xiang Cui
Keyword(s):  
High Speed ◽  
Noise Source ◽  
Radiation Power ◽  
Spectral Characteristics ◽  
Radiation Energy ◽  
Simulation Method ◽  
Acoustic Power ◽  
Broadband Noise ◽  
Aerodynamic Noise ◽  
High Speed Train

For high speed trains running at 300km/h or more, the aerodynamic noise becomes the primary noise source. A good knowledge of the location, spectral characteristics and propagation behavior of the noise source and the corresponding methods to reduce the effect of the aerodynamic noise are of crucial necessity during the design process of the high speed train. Based on the Lighthill Analogy, the pressure fluctuation of air at the surface of the train is acquired by simulating the flow field of a CRH3 high speed train running at 200 km/h, 300 km/h, 400 km/h and 500km/h by means of large eddy simulation method. By Fourier transformation, the distribution and the spectral characteristics of the surface acoustic dipole sources are obtained. The analysis of the results shows that the aerodynamic noise of the high speed train is a broadband noise with a strong radiation power band from 50Hz to 1000Hz. The dipole acoustic power calculated by statistically averaged on train surface is found to be proportional to the sixth power of running speed of the high speed train. The first and second bogie, the inter-car gap, the air deflector of the power train and the train nose of the last wagon are the main noise sources that contain high radiation energy.

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.

Effect of different typical high speed train pantograph recess configurations on aerodynamic noise

2020 ◽  
pp. 095440972094751
Author(s):  
Hogun Kim ◽  
Zhiwei Hu ◽  
David Thompson
Keyword(s):  
Unsteady Flow ◽  
High Speed ◽  
Flow Characteristics ◽  
Vortical Flow ◽  
Aerodynamic Noise ◽  
Upstream Region ◽  
High Speed Train ◽  
Detached Eddy Simulation ◽  
Noise Sources ◽  
Cavity Configuration

For high-speed trains, the aerodynamic noise becomes an essential consideration in the train design. The pantograph and pantograph recess are recognised as important sources of aerodynamic noise. This paper studies the flow characteristics and noise contributions of three typical high-speed train roof configurations, namely a cavity, a ramped cavity and a flat roof with side insulation plates. The Improved Delayed Detached-Eddy Simulation approach is used for the flow calculations and the Ffowcs Williams & Hawkings aeroacoustic analogy is used for far-field acoustic predictions. Simulations are presented for a simplified train body at 1/10 scale and 300 km/h with these three roof configurations. In each case, two simplified pantographs (one retracted and one raised) are located on the roof. Analysis of the flow fields obtained from numerical simulations clearly shows the influence of the train roof configuration on the flow behaviour, including flow separations, reattachment and vortex shedding, which are potential noise sources. A highly unsteady flow occurs downstream when the train roof has a cavity or ramped cavity due to flow separation at the cavity trailing edge, while vortical flow is generated by the side insulation plates. For the ramped cavity configuration, moderately large pressure fluctuations appear on the cavity outside walls in the upstream region due to unsteady flow from the upstream edge of the plate. The raised pantograph, roof cavity, and ramped cavity are identified as the dominant noise sources. When the retracted pantograph is located in the ramped roof cavity, its noise contribution is less important. Furthermore, the insulation plates also generate tonal components in the noise spectra. Of the three configurations considered, the roof cavity configuration radiates the least noise at the side receiver in terms of A-weighted level.

scholarly journals Characteristics and Mechanism Analysis of Aerodynamic Noise Sources for High-Speed Train in Tunnel

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Xiao-Ming Tan ◽  
Hui-fang Liu ◽  
Zhi-Gang Yang ◽  
Jie Zhang ◽  
Zhong-gang Wang ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Flow Field ◽  
Sound Source ◽  
High Speed ◽  
Spectral Characteristics ◽  
Oscillation Mode ◽  
Scale Model ◽  
Aerodynamic Noise ◽  
High Speed Train ◽  
Noise Sources

We aim to study the characteristics and mechanism of the aerodynamic noise sources for a high-speed train in a tunnel at the speeds of 50 m/s, 70 m/s, 83 m/s, and 97 m/s by means of the numerical wind tunnel model and the nonreflective boundary condition. First, the large eddy simulation model was used to simulate the fluctuating flow field around a 1/8 scale model of a high-speed train that consists of three connected vehicles with bogies in the tunnel. Next, the spectral characteristics of the aerodynamic noise source for the high-speed train were obtained by performing a Fourier transform on the fluctuating pressure. Finally, the mechanism of the aerodynamic noise was studied using the sound theory of cavity flow and the flow field structure. The results show that the spectrum pattern of the sound source energy presented broadband and multipeak characteristics for the high-speed train. The dominant distribution frequency range is from 100 Hz to 4 kHz for the high-speed train, accounting for approximately 95.1% of the total sound source energy. The peak frequencies are 400 Hz and 800 Hz. The sound source energy at 400 Hz and 800 Hz is primarily from the bogie cavities. The spectrum pattern of the sound source energy has frequency similarity for the bottom structure of the streamlined part of the head vehicle. The induced mode of the sound source energy is probably the dynamic oscillation mode of the cavity and the resonant oscillation mode of the cavity for the under-car structure at 400 Hz and 800 Hz, respectively. The numerical computation model was checked by the wind tunnel test results.

Aerodynamic behavior of a high-speed train with a braking plate mounted in the region of inter-car gap or uniform-car body: A comparative numerical study

2020 ◽  
pp. 095440972096582
Author(s):  
Jiqiang Niu ◽  
Yueming Wang ◽  
Feng Liu ◽  
Rui Li
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Numerical Study ◽  
Aerodynamic Performance ◽  
Body Region ◽  
High Speed Train ◽  
Detached Eddy Simulation ◽  
Continuous Increase ◽  
Car Body

The continuous increase in train speed has brought serious challenges to train braking safety. Aerodynamic braking technology can effectively improve the braking effect of trains at high speeds. In this study, an aerodynamic braking device installed in the inter-car gap region (ICG) of a high-speed train is proposed and the aerodynamic performance of the high-speed train with an aerodynamic braking device is assessed by improved delayed detached eddy simulation (IDDES) based on the κ-ω turbulence model. The results show that the opening of the plate significantly changes the aerodynamic performance of the train, thereby greatly increasing the aerodynamic forces of the train and their fluctuation degree. The effect of the opening of the plate increases the turbulence of the downstream flow field around the tail car. The affected area is mainly concentrated in the flow field around the location of the plate for the pressure field and the whole flow field behind the plate for the velocity field. The effect of the plate mounted on the uniform-car body region (UCG) on increasing the aerodynamic drag is better than that at the ICG, though the aerodynamic fluctuation and the influence on the surrounding flow field will also be great.

scholarly journals The coupled effects of bending and torsional flexural modes of a high-speed train car body on its vertical ride quality

2019 ◽  
Vol 233 (4) ◽  
pp. 979-993 ◽  
Author(s):  
Vahid Bokaeian ◽  
Mohammad A Rezvani ◽  
Robert Arcos
Keyword(s):  
Analytical Model ◽  
Quality Index ◽  
High Speed ◽  
Ride Quality ◽  
Vertical Acceleration ◽  
Beam Model ◽  
High Speed Train ◽  
Flexural Mode ◽  
Car Body ◽  
Rail Irregularities

This study is focused on the effects of bending and torsional flexural modes of the car body on the ride quality index of a high-speed train vehicle. The Euler–Bernoulli beam model is used to extract an analytical model for a high-speed train vehicle car body in order to investigate its bending and torsional flexural vibrations. The rigid model includes a car body, two bogie frames, and four wheelsets such that, each mass has three degrees of freedom including vertical displacement, pitch motion, and roll motion. The results obtained with the proposed analytical model are compared with experimental measurements of the car body response of a Shinkansen high-speed train. Moreover, it is determined that the bending and torsional flexural modes have significant effects on the vertical acceleration of the car body, particularly in the 9–15 Hz frequency range. Furthermore, the ride quality index is calculated according to the EN 12299 standard and it is shown that the faster the train the more affected is the ride quality by the flexural modes. In addition, the effect of coherence between two rail irregularities (the right and the left rails) on the results of the simulation is investigated. The results conclude that if the irregularities are completely correlated the torsional flexural mode of the car body does not appear in the response. Also, the first bending flexural mode in such cases is more excited compared with the partially correlated or uncorrelated rail irregularities. Therefore, the ride quality index in completely correlated cases is higher than other cases.

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