scholarly journals Multi-Source Coupling Based Analysis of the Acoustic Radiation Characteristics of the Wheel–Rail Region of High-Speed Railways

Entropy ◽  
2021 ◽  
Vol 23 (10) ◽  
pp. 1328
Author(s):  
Bowen Hou ◽  
Jiajing Li ◽  
Liang Gao ◽  
Di Wang
Keyword(s):  
Noise Reduction ◽  
High Speed ◽  
Acoustic Radiation ◽  
Low Frequency ◽  
Noise Model ◽  
Aerodynamic Noise ◽  
Rail Systems ◽  
Total Noise ◽  
Combined Simulation ◽  
Rolling Noise

Based on elastic mechanics, the fluid–structure coupling theory and the finite element method, a high-speed railway wheel-rail rolling-aerodynamic noise model is established to realize the combined simulation and prediction of the vibrations, rolling noise and aerodynamic noise in wheel-rail systems. The field test data of the Beijing–Shenyang line are considered to verify the model reliability. In addition, the directivity of each sound source at different frequencies is analyzed. Based on this analysis, noise reduction measures are proposed. At a low frequency of 300 Hz, the wheel-rail area mainly contributes to the aerodynamic noise, and as the frequency increases, the wheel-rail rolling noise becomes dominant. When the frequency is less than 1000 Hz, the radiated noise fluctuates around the cylindrical surface, and the directivity of the sound is ambiguous. When the frequency is in the middle- and high-frequency bands, exceeding 1000 Hz, both the rolling and total noise exhibit a notable directivity in the directions of 20–30° and 70–90°, and thus, noise reduction measures can be implemented in these directions.

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.

108 Effect of Aerodynamic Noise Reduction on High-speed Pantograph with Porous Metal

2008 ◽  
Vol 2008.18 (0) ◽  
pp. 55-58
Author(s):  
Takeshi SUEKI ◽  
Mitsuru IKEDA ◽  
Takehisa TAKAISHI ◽  
Takeshi KURITA ◽  
Haruo YAMADA
Keyword(s):  
Noise Reduction ◽  
High Speed ◽  
Porous Metal ◽  
Aerodynamic Noise

Complex structured polymer concrete sleeper for rolling noise reduction of high-speed train system

2019 ◽  
Vol 223 ◽  
pp. 110944 ◽  
Author(s):  
Sangkeun Ahn ◽  
Semin Kwon ◽  
Yeon-Taek Hwang ◽  
Hyo-In Koh ◽  
Hak-Sung Kim ◽  
...  
Keyword(s):  
Noise Reduction ◽  
High Speed ◽  
Polymer Concrete ◽  
High Speed Train ◽  
Rolling Noise ◽  
Train System

The generation of sound in turbulent motion

2008 ◽  
Vol 112 (1133) ◽  
pp. 381-394 ◽  
Author(s):  
G. M. Lilley
Keyword(s):  
Noise Reduction ◽  
Turbulent Flows ◽  
High Speed ◽  
Experimental Studies ◽  
Supersonic Jet ◽  
Jet Noise ◽  
Aerodynamic Noise ◽  
Turbulent Shear ◽  
Noise Generation ◽  
Physical Mechanisms

Abstract The present paper reviews and discusses the physical mechanisms of noise generation and reduction in turbulent flows with their applications towards aircraft noise reduction at takeoff and on the approach. This work began in 1948 when Lilley undertook an experimental investigation into the source of jet noise as a necessary precursor to finding methods for the reduction of high speed jet engine noise on civil jet airliners. Westley and Lilley completed this experimental programme in 1951, which included the design of a range of devices for high speed jet noise reduction. It was about this time that similar studies on jet noise were being started elsewhere and in particular by Lassiter and Hubbard in USA. The major contribution to the subject of turbulence as a source of noise came from Sir James Lighthill’s remarkable theory in 1952. In spite of the difficulties attached to theoretical and experimental studies on noise from turbulence, it is shown that with the accumulated knowledge on aerodynamic noise over the past 50 years, together with an optimisation of aircraft operations including flight trajectories, we are today on the threshold of approaching the design of commercial aircraft with turbofan propulsion engines that will not be heard above the background noise of the airport at takeoff and landing beyond 1-2km, from the airport boundary fence. It is evident that in the application of this work, which centres on the physical mechanisms relating to the generation of noise from turbulence and turbulent shear flows, to jet noise, there is not one unique mechanism of jet noise generation for all jet Mach numbers. This author in this publication has concentrated on what appears to be the dominant mechanism of noise generation from turbulence, where the mean convection speeds of the turbulence are subsonic. The noise generated at transonic and supersonic jet speeds invariably involves extra mechanisms, which are only briefly referred to here.

G201 Low-frequency aerodynamic noise from a high-speed train

2007 ◽  
Vol 2007 (0) ◽  
pp. _G201-1_-_G201-4_
Author(s):  
Hajime TAKAMI ◽  
Katsuhiro KIKUCHI ◽  
Hiroshi MAEKAWA ◽  
Takeshi KURITA ◽  
Yusuke WAKABAYASHI
Keyword(s):  
High Speed ◽  
Low Frequency ◽  
Aerodynamic Noise ◽  
High Speed Train

Modeling and Prediction of Cutting Noise in the Face-Milling Process

2007 ◽  
Vol 129 (3) ◽  
pp. 527-530 ◽  
Author(s):  
Karthikeyan Sampath ◽  
Shiv G. Kapoor ◽  
Richard E. DeVor
Keyword(s):  
High Speed ◽  
Cutting Speed ◽  
Milling Process ◽  
Face Milling ◽  
Aerodynamic Noise ◽  
Noise Prediction ◽  
Vibration Data ◽  
Total Noise ◽  
Workpiece Vibration ◽  
The Face

A cutting noise prediction model is developed to relate the cutter-workpiece vibrations to the sound pressure field around the cutter in the high-speed face-milling process. The cutter-workpiece vibration data are obtained from a dynamic mechanistic face-milling force simulation model. The total noise predicted, based on both cutting noise and aerodynamic noise prediction, compares well to the noise observed experimentally in the face-milling process. Using the model, the effects of various machining and cutter geometry parameters are studied. It is shown that cutter geometry, machine dynamics, and cutting speed all play important roles in determining overall noise in face milling.

scholarly journals POD and Fourier analyses of a fluid-structure-acoustic interaction problem related to interior car noise

2017 ◽  
Vol 18 (2) ◽  
pp. 201
Author(s):  
Éric Gaudard ◽  
Philippe Druault ◽  
Régis Marchiano ◽  
François Van Herpe
Keyword(s):  
Pressure Field ◽  
Acoustic Radiation ◽  
Numerical Study ◽  
Low Frequency ◽  
Wall Pressure ◽  
Aerodynamic Noise ◽  
Frequency Noise ◽  
Post Processing ◽  
Fourier Decomposition ◽  
Frequency Decomposition

In order to approach a flow configuration revealing the aerodynamic noise contribution in the interior of road vehicles due to the A-pillar vortex, a numerical simulation of a Forward Facing Step (FFS) coupled with a vibrating structure is performed. This numerical study is based on a weak coupling of three solvers to compute (i) the flow field in interaction with the FFS, (ii) the vibration of the structure and (iii) the acoustic radiation in the open cavity. The purpose of this work is then to evaluate the ability of two different post-processing methods: Proper Orthogonal Decomposition and Fourier Decomposition to identify the origin of the noise radiated into a cavity surrounded by an unsteady flow. Fourier and POD decompositions are then successively performed to extract the part of the aeroacoustic wall pressure field impacting the upper part of an upward step mainly related to the radiated acoustic pressure in the cavity. It is observed that the acoustic part, extracted from the wavenumber frequency decomposition (Fourier analysis) of the wall pressure field generates a non-negligible part of the interior cavity noise. However, this contribution is of several orders smaller than the one related to the aerodynamic part of the pressure field. Moreover, it is shown that the most energetic part of the pressure field (POD analysis) is due to the shear flapping motion and mainly contributes to the low-frequency noise in the cavity. Such post-processing results are of particular interest for future analyzes related to the noise radiated inside a car.

scholarly journals Complexity Simulation on Application of Asymmetric Bionic Cross-Section Rod in Pantographs of High-Speed Trains

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Yan Cao ◽  
Yu Bai ◽  
Qiangfeng Wang
Keyword(s):  
Noise Reduction ◽  
Porous Materials ◽  
Cross Section ◽  
High Speed ◽  
Aerodynamic Resistance ◽  
Aerodynamic Noise ◽  
Practical Application ◽  
Bionic Design ◽  
High Speed Trains ◽  
Bionic Structure

Ground transportation means and aircrafts with high-speed running are composed of many rod components. Aerodynamic noise generated therefrom is very outstanding. Reduction of the aerodynamic noise of rods becomes a hot topic in recent years. Most reported studies are tentative researches on aerodynamic noise of a pantograph or involve noise reduction of the pantograph with using porous materials or reshaping rod surfaces. Through using porous materials and reshaping rod surface, the aerodynamic noise of pantograph can be reduced to a certain extent, but the aerodynamic resistance will be increased and it is not convenient for practical application in engineering. Regarding this situation, the paper explores noise reduction performance of a feather on the back of a carrier pigeon and conducts the bionic design on rod surface. Through numerical simulation, the paper researches noise reduction performance of the bionic structure on the rod surface, reveals the mechanism of bionic noise reduction, and explores noise reduction effects of bionic structural rods on pantographs of the high-speed trains.

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