Investigation for insertion loss of noise barrier for sound source moving at high speed

This study is concerned with the theoretical solution to the problem of sound screening by simple hard barriers on the ground with special emphasis given to the type of wave incidence, namely a comparison between the use of either a spherical or a cylindrical sound source. For a receiver at the shadow of the noise source, the field may be assumed to be due to the edge wave and for this, exact solutions are used. Regarding the wave reflection on an impedance ground, exact formulations are also used, and finally, some calculations are made on the performance of a hard noise barrier on a two-impedance ground. As a conclusion, it is found that although the sound level at the receiver may show some small differences depending on the frequency and on the geometry of the problem, the overall insertion loss of the thin hard barrier is almost the same for the spherical and the line source, and the differences are found to amount to less than 1 dB for geometries of practical occurrence.

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Analysis on Traffic Noise Attenuation by Using Sound Barrier

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.584-586.776 ◽

2014 ◽

Vol 584-586 ◽

pp. 776-779

Author(s):

Xian Feng Huang ◽

Chen Hui Zhu ◽

Quan Shi

Keyword(s):

Sound Source ◽

Insertion Loss ◽

Traffic Noise ◽

Noise Attenuation ◽

Noise Barriers ◽

Sound Barrier ◽

Noise Barrier ◽

Significant Attenuation ◽

Infinite Line ◽

Insertion Losses

By applying noise insertion loss predicting model of the noise barriers, influencing factors on insertion loss of the sound barrier are investigated for achieving the significant attenuation effects. In term of the infinite line sound source and the finite length of the barriers, the sound insertion losses with varying parameters are calculated and compared. Finally, the meaningful results indicate that the economic and reasonable height and length of the noise barrier are gained to be beneficial for barrier design.

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A study on the insertion loss of a noise barrier for a directional sound source.

Journal of the Acoustical Society of Japan (E) ◽

10.1250/ast.20.325 ◽

1999 ◽

Vol 20 (4) ◽

pp. 325-328 ◽

Cited By ~ 2

Author(s):

Gensei Matsumoto ◽

Kyoji Fujiwara ◽

Akira Omoto

Keyword(s):

Sound Source ◽

Insertion Loss ◽

Noise Barrier

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Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

Noise Control Engineering Journal ◽

10.3397/1/376826 ◽

2020 ◽

Vol 68 (4) ◽

pp. 303-314

Author(s):

Yuna Park ◽

Hyo-In Koh ◽

University of Science and Technology, Transpo ◽

...

Keyword(s):

High Speed ◽

Field Tests ◽

Residential Areas ◽

Railway Systems ◽

Railway Noise ◽

Sound Levels ◽

Noise Barrier ◽

The Difference ◽

Reduction Effect ◽

The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

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High-speed electro-optic switch using buried electrode structure in polymer Mach–Zehnder waveguide

Modern Physics Letters B ◽

10.1142/s0217984916500639 ◽

2016 ◽

Vol 30 (06) ◽

pp. 1650063 ◽

Cited By ~ 1

Author(s):

Jingwen Sun ◽

Jian Sun ◽

Yunji Yi ◽

Lucheng Qv ◽

Shiqi Sun ◽

...

Keyword(s):

Insertion Loss ◽

Rise Time ◽

High Speed ◽

Low Cost ◽

Characteristic Parameters ◽

Electrode Structure ◽

Processing Cost ◽

Electro Optic ◽

Disperse Red 1 ◽

Excellent Photostability

A low-cost and high-speed electro-optic (EO) switch using the guest–host EO material Disperse Red 1/Polymethyl Methacrylate (DR1/PMMA) was designed and fabricated. The DR1/PMMA material presented a low processing cost, an excellent photostability and a large EO coefficient of 13.1 pm/V. To improve the performance of the switch, the in-plane buried electrode structure was introduced in the polymer Mach–Zehnder waveguide to improve the poling and modulating efficiency. The characteristic parameters of the waveguide and the electrodes were carefully designed and the fabrication process was strictly controlled. Under 1550 nm, the insertion loss of the device was 12.7 dB. The measured switching rise time and fall time of the switch were 50.00 ns and 54.29 ns, respectively.

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An investigation into high-speed train interior noise with operational transfer path analysis method

Railway Engineering Science ◽

10.1007/s40534-021-00235-0 ◽

2021 ◽

Author(s):

Muxiao Li ◽

Ziwei Zhu ◽

Tiesong Deng ◽

Xiaozhen Sheng

Keyword(s):

Sound Source ◽

Reference Point ◽

Source Identification ◽

High Speed ◽

Interior Noise ◽

Target Point ◽

High Speed Train ◽

Transfer Path ◽

Sound Source Identification ◽

Transfer Path Analysis

AbstractPassengers' demands for riding comfort have been getting higher and higher as the high-speed railway develops. Scientific methods to analyze the interior noise of the high-speed train are needed and the operational transfer path analysis (OTPA) method provides a theoretical basis and guidance for the noise control of the train and overcomes the shortcomings of the traditional method, which has high test efficiency and can be carried out during the working state of the targeted machine. The OTPA model is established from the aspects of "path reference point-target point" and "sound source reference point-target point". As for the mechanism of the noise transmission path, an assumption is made that the direct sound propagation is ignored, and the symmetric sound source and the symmetric path are merged. Using the operational test data and the OTPA method, combined with the results of spherical array sound source identification, the path contribution and sound source contribution of the interior noise are analyzed, respectively, from aspects of the total value and spectrum. The results show that the OTPA conforms to the calculation results of the spherical array sound source identification. At low speed, the contribution of the floor path and the contribution of the bogie sources are dominant. When the speed is greater than 300 km/h, the contribution of the roof path is dominant. Moreover, for the carriage with a pantograph, the lifted pantograph is an obvious source. The noise from the exterior sources of the train transfer into the interior mainly through the form of structural excitation, and the contribution of air excitation is non-significant. Certain analyses of train parts provide guides for the interior noise control.

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Insertion loss by concrete noise barrier - Acoustical testing and computational simulation

10.2514/6.2000-1985 ◽

2000 ◽

Author(s):

O. Baysal ◽

M. Idres ◽

J. Kelly

Keyword(s):

Insertion Loss ◽

Computational Simulation ◽

Noise Barrier

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High-Speed Δβ-Reversal Directional Coupler Modulator with Low Insertion Loss for 1.3 μm in LiNbO3

Journal of Optical Communications ◽

10.1515/joc-1984-0103 ◽

1984 ◽

Vol 5 (1) ◽

Author(s):

F. Auracher ◽

D. Schicketanz ◽

K.-H. Zeitler

Keyword(s):

Insertion Loss ◽

High Speed ◽

Directional Coupler ◽

Low Insertion Loss ◽

Directional Coupler Modulator

SummaryWe report on a very fast (≥ 6 Gbit/s) Δβ-reversal directional-coupler modulator with low insertion loss (2 dB) for 1.3 μm wavelength operation. The design of the modulator permits easy and reproducible fabrication.

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