Railway applications. Noise emission. Rail roughness measurement related to rolling noise generation

2009 ◽  
Keyword(s):  
Noise Generation ◽  
Roughness Measurement ◽  
Noise Emission ◽  
Rolling Noise

Surface Topography and Noise Emission in Gearboxes

1997 ◽  
Author(s):  
Naser Amini ◽  
B. G. Rosén
Keyword(s):  
Experimental Investigation ◽  
Total Energy ◽  
Surface Topography ◽  
Noise Generation ◽  
Test Rig ◽  
Noise Emission ◽  
Applied Torque ◽  
Surface Topographies ◽  
Before And After ◽  
Noise Assessment

Abstract This paper, by the experimental investigation, deals with the effect of different surface topographies on noise generation in gears. Results from the noise assessment of one gear before and after honing are discussed. The honing operation was applied to the gear after the grinding. The gear was tested in an actual gearbox, operated in a test rig. Running conditions were systematically changed during the test; however, the same conditions were utilized for the gear before and after honing. The aim of the study was to identify the mechanism of the expected noise reduction, with surfaces being evaluated in 3D. The following results have been obtained: The total energy in the noise decreases significantly. The magnitude of the tooth-mesh frequency dose not change, but the level of its higher harmonics decreases significantly. These reductions are especially significant, when running at higher rotational speeds or when the applied torque is increased.

High speed train noise emission: Latest investigation of the aerodynamic/rolling noise contribution

2006 ◽  
Vol 293 (3-5) ◽  
pp. 535-546 ◽  
Author(s):  
C. Mellet ◽  
F. Létourneaux ◽  
F. Poisson ◽  
C. Talotte
Keyword(s):  
High Speed ◽  
High Speed Train ◽  
Noise Emission ◽  
Rolling Noise ◽  
Noise Contribution

Reduction of Noise at the Design Stage: A Case Study of a Lightly Loaded Assembly

1969 ◽  
Vol 184 (1) ◽  
pp. 593-614 ◽  
Author(s):  
M. A. Satter ◽  
B. Downs ◽  
G. R. Wray
Keyword(s):  
Analytical Study ◽  
Design Stage ◽  
Acoustic Absorption ◽  
Noise Generation ◽  
Noise Emission ◽  
Design Changes ◽  
Damping Materials ◽  
Lower Noise ◽  
Made In

An experimental and analytical study is made of the noise emission from the drawroll assembly of a textile draw-twisting machine. As an alternative to resorting to acoustic absorption techniques or the use of expensive high damping materials, investigations are made into the basic method of noise generation in the assembly. This leads to the incorporation of small design changes and the significantly lower noise emission thereby achieved is compared with the original emission. Aimed at the machine designer, the presentation is made in a straightforward, non-mathematical fashion.

scholarly journals Acoustic characteristics of a ported shroud turbocompressor operating at design conditions

2018 ◽  
Vol 21 (8) ◽  
pp. 1454-1468 ◽  
Author(s):  
Sidharath Sharma ◽  
Alberto Broatch ◽  
Jorge García-Tíscar ◽  
John M Allport ◽  
Ambrose K Nickson
Keyword(s):  
Decomposition Methods ◽  
Broadband Noise ◽  
Stable Operation ◽  
Noise Generation ◽  
Noise Emission ◽  
Spectral Signatures ◽  
Surge Margin ◽  
Flow Enhancement ◽  
Ported Shroud ◽  
The Impact

In this article, the acoustic characterisation of a turbocharger compressor with ported shroud design is carried out through the numerical simulation of the system operating under design conditions of maximum isentropic efficiency. While ported shroud compressors have been proposed as a way to control the flow near unstable conditions in order to obtain a more stable operation and enhance deep surge margin, it is often assumed that the behaviour under stable design conditions is characterised by a smooth, non-detached flow that matches an equivalent standard compressor. Furthermore, research is scarce regarding the acoustic effects of the ported shroud addition, especially under the design conditions. To analyse the flow field evolution and its relation with the noise generation, spectral signatures using statistical and scale-resolving turbulence modelling methods are obtained after successfully validating the performance and acoustic predictions of the numerical model with experimental measurements. Propagation of the frequency content through the ducts has been estimated with the aid of pressure decomposition methods to enhance the content coming from the compressor. Expected acoustic phenomena such as ‘buzz-saw’ tones, blade passing peaks and broadband noise are correctly identified in the modelled spectrum. Analysis of the flow behaviour in the ported shroud shows rotating structures through the slot that may impact the acoustic and vibration response. Further inspection of the pressure field through modal decomposition confirms the influence of the ported shroud cavity in noise generation and propagation, especially at lower frequencies, suggesting that further research should be carried out on the impact these flow enhancement solutions have on the noise emission of the turbocharger.

Accurate and controled vehicle pass-by noise emission quantification in real life traffic

2021 ◽  
Vol 263 (1) ◽  
pp. 5233-5245
Author(s):  
Lucille Pinel Lamotte ◽  
Fabien Lepercque ◽  
Valentin Baron
Keyword(s):  
Video Processing ◽  
Real Life ◽  
Health Impact ◽  
Source Model ◽  
Noise Emission ◽  
Noise Sources ◽  
Eu Directive ◽  
Mems Technology ◽  
The Individual ◽  
Rolling Noise

Noise emission from individual vehicle largely contributes to city pollution and has serious health impact. The standards towards vehicle manufactures consists in pass-by testing with specific acceleration conditions which are not representative of all real driving. For the 2015/996 EU directive, the vehicle source model is inspired of the preceding pass-by standard with derived data represented the propulsion and rolling noise sources. Anyhow, those sources are underestimated due to driving behavior, aged and modified vehicle, road surface, meteorological conditions... The true data collection of vehicle pass-by would be interesting. Moreover, some of the countries are reflecting on how to fight against those extremely noisy vehicle exceeding noise limit with efficient monitoring systems. This paper presents an innovative tool able to detect, identify and quantify the noise emission of individual pass-by vehicle in real life traffic. It is based on the combination of array and video processing. Compared to the state of the art and thanks to MEMs technology, the system is optimized and designed to quantify the individual noise vehicle emission regarding standard with controlled measurement and accurate processing. If the conditions are not respected to properly qualify the pass-by regarding the system limits, the data are ignored. It aims at constructing large and accurate database useful to determine average noise levels and/or acceptable noise limits per vehicle category.

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