scholarly journals The optimum orientation of an absorbing barrier

2005 ◽  
Vol 461 (2060) ◽  
pp. 2369-2383 ◽  
Author(s):  
A.D Rawlins
Keyword(s):  
Noise Level ◽  
Noise Source ◽  
Shadow Region ◽  
Source Position ◽  
Absorbent Material ◽  
Noise Barrier ◽  
Receiver Point

In the following work, we solve the problem of the best orientation of a rigid noise barrier, which has one face lined with absorbent material, between a noise source and a receiver point in the shadow region of the barrier. By the ‘best orientation’, we mean that positioning of the barrier which yields the least noise level at the receiving point for a given barrier and source position.

Research of Different Noise Barriers Efficiency at Different Temperature

2017 ◽  
Author(s):  
Tomas Vilniškis ◽  
Tomas Januševicius
Keyword(s):  
Air Temperature ◽  
Noise Level ◽  
Structural Changes ◽  
Field Measurements ◽  
Sound Waves ◽  
Noise Barriers ◽  
Different Temperatures ◽  
Noise Measurements ◽  
Noise Barrier ◽  
Key Aspects

In this article was analyzed acoustic efficiency of two different construction noise barriers. Field measurements of noise tests were carried out before and behind a wooden barrier, which height was 2.9 meters and a wooden wall with equipped roof, which height was 3.2 m. As is known the length of the wall, height, surface roughness, shape and material of the wall – key aspects of determining the effectiveness of noise barrier. Different materials, depending on their characteristics of the hard or soft, porous or dense, interact differently with the sound of waves. Article contains research results of noise measurements at positive and negative air temperature. There analyzing wooden noise barrier acoustic efficiency at different temperatures and the effects of temperature to the diffraction of sound waves through the peak of the barrier. Test results show, that noise barrier without structural changes reduced noise level to 14–22 dB, noise barrier with structural changes reduced noise level to 20–23,1 dB, when air temperature was positive. When air temperature was negative, noise barrier without structural changes reduced noise level to 15,5–21,4 dB, noise level with structural changes to 19–26,6 dB.

Reducing Compressor Station Ambient Noise Level by Controlling Compressor Internal Noise Source

2002 ◽  
Author(s):  
Zheji Liu ◽  
Bill Jahnke ◽  
Mike Marczak ◽  
Paul Kiteck
Keyword(s):  
Noise Level ◽  
High Efficiency ◽  
Noise Source ◽  
Internal Noise ◽  
Sound Intensity ◽  
Control Device ◽  
Third Party ◽  
Intensity Level ◽  
Compressor Station ◽  
Compressor Building

Dresser-Rand single stage pipeline booster compressors have been popular for gas transmission applications due to their high efficiency. As more compressors are installed in natural gas compressor stations close to populated areas, the noise level emitted from the compressor stations becomes a concern. To address the potential community noise concerns, Dresser-Rand recently developed a very effective noise control device — the Duct Resonator array or DR array, to attenuate the internal noise of the compressor, which is typically a major noise source of a compressor station. This technology has been validated by extensive in-house experimental study to be acoustically effective and yet have no measurable adverse effect on aerodynamic performance. This paper discusses the application of DR arrays in two compressors that are in-service at a Williams Gas Pipeline compressor station. Note: the DR arrays are now included in the third unit addition. A successful collaboration among the compressor manufacturer, the compressor user, and a third party acoustics expert was coordinated to take acoustic measurements independently to evaluate the noise reduction provided by the DR arrays. The comprehensive acoustic data acquisition included sound pressure level and sound intensity level measurements around each of the two compressors and several noise level surveys both inside and outside of the compressor building. Noise testing was first performed on each of the two compressors prior to the installation of the DR arrays and was repeated after the compressor hardware modification with DR arrays. A comparison of the noise data recorded before and after the installation of the DR arrays confirmed that the compressor noise level inside the compressor building and the noise level outside of the building were reduced significantly. The DR array has proved to be an efficient and effective device for reducing noise and vibration levels of both existing and new centrifugal compressors and associated piping.

scholarly journals Operational Noise Assessment in an Open Cycle Power Plant: Study on the Existing Acoustical Performance.

2018 ◽  
Vol 7 (4.35) ◽  
pp. 11 ◽  
Author(s):  
Helmi A Halim ◽  
Gasim Hayder
Keyword(s):  
Power Plant ◽  
Noise Level ◽  
Performance Study ◽  
Noise Barriers ◽  
Noise Assessment ◽  
Noise Barrier ◽  
Open Cycle ◽  
Gas Turbine Power Plant ◽  
The Impact

This research is an acoustical performance study in an open cycle peaking gas turbine power plant located at the southern coast of Peninsula Malaysia. Referring to its location at the middle of residence and tourism area, throughout its operation years, several complains from public has been lodged about the excessive operational noise at the perimeter of the plant and statistically from the last decade, twenty-four (24) noise related public complains were recorded. This issue has initiated a study to determine the current operational noise level as well as the effectiveness of the existing noise barriers. Based on EIA approval, the boundary noise for the operation should be limited to 55 dB(A) at any time. The field measurement of noise level at two (2) different locations are assessed in-situ and continuously noise monitoring covering all the plant’s operational regime and at different plant operational pattern. These results are compared with the initial noise report during its early year of operation in 1999. Finally the hypotheses then compared with the referenced legislations. Results from all the methodologies show the current operational noise level of the plant are within the permissible limit, however the overall operational noise of the plant is increasing compared with 1999 report due to the increasing of surrounding activities as well as deteriorating of current engineering and natural noise barrier arrangement. Mitigation plans has been recommended to the management to minimize the impact of the excessive noise to surrounding residence and to the plant workers. On top of that, the theoretical and commercial implication of the research is also discussed.

NOISE SHIELDING BY SIMPLE BARRIERS: COMPARISON BETWEEN THE PERFORMANCE OF SPHERICAL AND LINE SOUND SOURCES

2000 ◽  
Vol 08 (03) ◽  
pp. 495-502 ◽  
Author(s):  
D. OUIS
Keyword(s):  
Sound Source ◽  
Insertion Loss ◽  
Line Source ◽  
Wave Reflection ◽  
Noise Source ◽  
Sound Level ◽  
Sound Sources ◽  
Noise Shielding ◽  
Noise Barrier ◽  
Wave Incidence

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.

Study on Acoustic Model of Transformer

2014 ◽  
Vol 1008-1009 ◽  
pp. 571-575
Author(s):  
Jing Zhu Hu ◽  
Di Chen Liu ◽  
Qing Fen Liao ◽  
Su Wei ◽  
Lei Yu
Keyword(s):  
Noise Level ◽  
Noise Control ◽  
Noise Source ◽  
Sound Field ◽  
Point Sources ◽  
Equivalent Model ◽  
Noise Prediction ◽  
Acoustic Model ◽  
Plane Source ◽  
Equivalent Source

The model of transformer as a noise source is very critical for substation noise prediction. The transformer is equivalent to several point sources on the basis of regarding the transformer as a combination of several planar sources. This equivalent model is based on equivalent source method and it is convenient and easy. The model of 9 equivalent point sources is simulated to verify that the rebuilt sound field is roughly the same as the actual sound field generated by the plane source. Moreover, the accuracy of the model with different settings was discussed. The acoustic model is accurate and feasible to calculate the noise level radiated by transformer and it is meaningful for substation noise control.

Noise Source Identification of the Grain Combining Harvester Based on Acoustic Array Test

2020 ◽  
Vol 36 (6) ◽  
pp. 879-890
Author(s):  
Yujun Shang ◽  
Chenglong Wang ◽  
Hongmei Xu ◽  
Shuang Liu ◽  
Wei Jiang ◽  
...  
Keyword(s):  
Source Identification ◽  
Noise Level ◽  
Noise Source ◽  
Noise Pollution ◽  
Rear Side ◽  
List Type ◽  
Frequency Range ◽  
Noise Source Identification ◽  
Combine Harvester ◽  
Acoustic Array

HIGHLIGHTSWe tested the noise of a grain combining harvester using a spiral acoustic array, aiming to identify its main sources and reduce its noise level.The noise of the harvester is mainly concentrated in the frequency range of 1 to 4 kHz.When the power of other devices is cut off, engine is the main noise source. While all devices are in normal working condition, the main source of noise is the header device and the intermediate conveying device.Abstract. The grain combine harvester is an important agricultural equipment with multiple functions of harvesting, threshing, separating, cleaning and grain gathering. As an instantaneous physical pollution, noise has become one of the main causes of modern civilization diseases. The noise generated by the operation of harvesters not only causes harm to the workers, but also leads to environmental noise pollution. Here, we tested the noise of a grain combine harvester using a spiral acoustic array, aiming to identify its main source by noise source identification technology based on the sound pressure distribution and reduce its noise level. The test results show that the noise of the harvester is mainly concentrated in the frequency range of 1 to 4 kHz. When the power of other devices is cut off, the engine is the main noise source, while under normal working conditions of all devices, the main source of noise is the header device and the intermediate conveying device on the front side of the harvester, the threshing device on the rear side, the engine and the threshing device on the left side, and the engine and the header device on the right side. Keywords: Acoustic array technology, Grain combining harvester, Noise source identification, Vibration and noise reduction.

scholarly journals STUDY ON EFFECTIVE NOISE BARRIER AT SENIOR HIGH SCHOOL (SMAN 02) CIBINONG

2019 ◽  
Vol 2 (2) ◽  
pp. 181
Author(s):  
Aulia Ramandha ◽  
Wisnu Eka Yulyanto ◽  
Sandra Madonna
Keyword(s):  
High School ◽  
Insertion Loss ◽  
Noise Level ◽  
Road Traffic ◽  
Traffic Noise ◽  
Road Traffic Noise ◽  
Type Ii ◽  
Noise Barrier ◽  
Barrier Type ◽  
The Difference

<strong>Aim:</strong> The aim of this study is to design noise barrier shapes and to investigate its effectiveness in reducing traffic noise at one public school in Indonesia. <strong>Methodology and Results:</strong> Two types of barriers were designed on a laboratory scale using plywood materials and the noise level was measured using Noise Analyzer Briiel and Kjaer Type 2250. Noise reduction was analyzed by using the Insertion Loss method based on the difference of the noise level before and after implementing the barrier. The results show that the barrier Type II with a length of 200 cm, a receiver height of 30 cm, and a curved shape of 45° angle (Type L) is more effective in reducing the noise than the other variation of barrier shape and length. Barrier Type L (Type II) can reduce the noise at high frequency between 1–8 kHz with an Insertion Loss value of 6.9–27.9 dB. <strong>Conclusion, significance and impact study:</strong> The noise barrier Type II, with specifications of 20 m length, 3 m height, and barrier material of reinforced concrete, is recommended to be used at the high school to reduce the road traffic noise.

scholarly journals Assessment of acoustic pollution of areas bordering highways

2021 ◽  
Vol 937 (2) ◽  
pp. 022055
Author(s):  
E V Antonenko ◽  
A Yu Melnichuk ◽  
V V Popovich
Keyword(s):  
Traffic Flow ◽  
Noise Level ◽  
Motor Vehicle ◽  
Noise Source ◽  
Research Result ◽  
Maximum Level ◽  
Vehicle Noise ◽  
Acoustic Load ◽  
The Republic

Abstract The work is devoted to the peculiarities of acoustic pollution of roadside territories. The studied territory is characterized by uneven acoustic load on the experimental sections of the highways of the Republic of Crimea, which is associated with the peculiarities of traffic flow and technical characteristics of cars. The article considers the indicators of the equivalent and maximum levels of motor vehicle noise. As the research result, the excess of noise level from 10 to 30 dBA was revealed. The maximum level of acoustic pollution was recorded in 10-meter zone, at a distance of 30 m from the noise source the level of acoustic pollution is reduced to 5-10 dBA.

scholarly journals The study for installing noise barrier on highway route no.9

2018 ◽  
Vol 169 ◽  
pp. 01012
Author(s):  
Chaddanai Jiradecha ◽  
Pruethipong Singhatiraj
Keyword(s):  
Traffic Congestion ◽  
Noise Level ◽  
Noise Pollution ◽  
Mathematic Model ◽  
Rapid Expansion ◽  
Noise Barriers ◽  
Sensitive Areas ◽  
The People ◽  
Noise Barrier ◽  
A New Technique

Highway Route No. 9 is a Bangkok bypass motorway that aims to alleviate traffic congestion in greater Bangkok areas. Presently, it is found a rapid expansion of new communities residing along both side of Highway No. 9. To lessen the noise level, Department of Highways installed the noise barrier on the sensitive locations. However, people from communities living on both sides of highway still demand some additional noise pollution improvement. To improve the efficiency of using noise barriers and to promote environmental and social quality for the people on the sensitive communities along the highway route, the Department of Highways, therefore, designs a new technique for installing noise barrier on the sensitive areas, i.e. education institutions, temple, residential area. In addition, the mathematic model is applied to 12 selected locations of sensitive areas for monitoring the effectiveness of the new installation technique. The mathematic model is used for predict the future noise level after installation of noise barrier in year 2037. The results confirm that the appropriate height and width of noise barrier can improve the comfortable of the people on the sensitive area.

Designing Roadside Noise Barrier

2018 ◽  
Vol 10 (2) ◽  
pp. 24-32
Author(s):  
Jason Obadiah
Keyword(s):  
Noise Source ◽  
Residential Area ◽  
Shadow Zone ◽  
Construction Sites ◽  
Noise Barriers ◽  
The Road ◽  
Sound Barrier ◽  
Additional Noise ◽  
Noise Barrier ◽  
The Common

Noise is the common problem in the residential area, whether it came from events, vehicles, construction sites, or urban area. The most affected residential area are usually the ones which adjacent to the highway or a road. When someone is overexposed from the noise, this could lead into many health problems. This is why a noise barrier is essential to be built along the road. problems regarding the noise barrier is that although the barrier can attenuates the noise from the traffic, there are other sound source, or in this case, noise source other than the traffic such as the airplane. This problem mostly happened on the residential ground around an airport. One of the solutions for these problems is by using vegetation as additional noise barriers. By doubling the barrier (noise barrier - vegetation) the attenuations will probably much higher, in accounts that the vegetation is much higher than the barrier so that if there are multiple floor buildings, the floors above will also provide with noise insulations. Although, it would be more appropriate to use acoustic treatments to the buildings. The other solution is that by using the concept of constructing a louver or cap atop the wall that is directed back toward the noise source. This concept follows the theory that such a design should inhibit shadow zone diffraction filling in sound behind the noise barrier. Keywords: noise, sound, barrier, attenuation

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