A Comparison of Two Different Sound Intensity Methods to Measure the Sound Power Level

In order to investigate the sound radiation characteristics of lightweight roof constructions when excited by rainfall, an artificial rainfall apparatus was constructed to simulate natural rainfall conditions. From the measurement results, it can be seen that the facility developed is practically applicable for the examination of the sound radiation characteristics of rain noise. It was therefore used in the measurement of sound power of 20 lightweight roofs. In addition, the relationship between sound power level and sound transmission loss measured by the sound intensity method was investigated statistically. As a result, it has been shown that a linear relationship exists between them and there is a possibility of estimating the sound power level from the transmission loss.

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Simulation and Analysis of the Radiated Acoustic Field Measurement of the Underwater Vehicle Based on NAH

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.503-504.1575 ◽

2012 ◽

Vol 503-504 ◽

pp. 1575-1579

Author(s):

Shao Chun Ding ◽

Lin Na Zhou ◽

Jing Jun Lou ◽

Shi Jian Zhu

Keyword(s):

Acoustic Field ◽

Sound Pressure ◽

Power Level ◽

Sound Intensity ◽

Sound Power ◽

Pressure Method ◽

Sound Power Level ◽

Measuring Surface ◽

Source Level ◽

The Mean

we use the NAH method for the simulation and analysis of sound power level and source level with the plan measuring surface under the same distance and size. The sound intensity integral method, the mean square sound pressure method and the NAH reversal method have been adopted in this paper. We also compare the sound power level between the plan measuring surface and the cylinder measuring surface, thus helps verifying the accuracy of the measurement of the radiated acoustic field based on the method of NAH. The conclusion we have drawn here can also provides dependable experimental basis for the choosing of measuring surfaces

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Sound Power Measurements in the Near Field of Transformers

ASME 2012 Noise Control and Acoustics Division Conference ◽

10.1115/ncad2012-1170 ◽

2012 ◽

Cited By ~ 1

Author(s):

Michael Ertl ◽

Hermann Landes

Keyword(s):

Sound Pressure ◽

Power Level ◽

Near Field ◽

Sound Field ◽

Sound Intensity ◽

Sound Level ◽

Numerical Analyses ◽

Sound Power ◽

3D Fem ◽

Sound Power Level

The international standard for the determination of the sound power level of transformers allows both the sound pressure and the sound intensity measurement method. Since the sound measurements take place in the reactive near-field next to the vibrating transformer tank walls, local disturbances influence the sound field characteristics at the measurement positions. As a result, the measured mean sound power level differs commonly up to 6dB at comparative measurements with both methods. Beyond these near field effects, the influence of an industrial measurement environment (background sound sources, hard-reflecting floor, semi-reverberant walls, and standing waves) to the sound pressure and sound intensity field characteristics is investigated. Hereby, numerical analyses based on 3D-FEM with consideration of the fluid-structure-coupling are used. The measured sound level differences can be re-produced and clarified in numerical analyses.

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Sound Intensity Mapping on Single Cylinder Direct Injection Diesel Engine with The Application of Palm Oil Methyl Ester Biodiesel

International Journal of Automotive and Mechanical Engineering ◽

10.15282/ijame.18.2.2021.21.0677 ◽

2021 ◽

Vol 18 (2) ◽

pp. 8833-8844

Author(s):

Mohd Shahrir Mohd Sani ◽

J.M. Zikri ◽

A. Abdul Adam

Keyword(s):

Methyl Ester ◽

Palm Oil ◽

Engine Speed ◽

Power Level ◽

Sound Intensity ◽

Sound Power ◽

Noise Emission ◽

Emission Analysis ◽

Intensity Mapping ◽

Sound Power Level

The utilisation of biodiesel nowadays has become familiar with rapid production types of biodiesel in order to replace the dependency on the fossil fuel parallel to the implementation of green technology that emphasises the products to be more environmental-friendly. Nevertheless, the emerges of various kinds of biodiesel cannot be simply used, despite using the biodiesel does not need any major modification on the engine; it still needs a few analyses that must be done to determine whether it will give advantages or disadvantages. Therefore, this research was carried out to investigate the effect of using palm oil methyl ester (POME) biodiesel on the engine in terms of noise emission. The sound intensity mapping method was used to indicate the effectiveness of the biodiesel by identifying the noise radiation. Along with the mapping, the sound power level (SPL) is also being obtained to provide a clear comparison between the parameters. Generally, switching up the engine speed and load increased the sound power level. Based on the results obtained related to the SPL, the intensity mapping tends to show a higher colour-coded in the noise source image for the higher engine speed and load setup. It was found that the engine speed and load give a significant contribution to noise emission produced by the engine, and it can be inferred that this method can be utilised to accomplish the noise emission analysis.

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Effect on Measurement of the Radiated Acoustic Field of Underwater Structure Based on NAH with Swinging Measuring Surface

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.197.778 ◽

2012 ◽

Vol 197 ◽

pp. 778-781

Author(s):

Lin Na Zhou ◽

Shao Chun Ding ◽

Ruo Yu Zhang ◽

Jing Jun Lou ◽

Shi Jian Zhu

Keyword(s):

Sound Pressure ◽

Power Level ◽

Near Field ◽

Sound Intensity ◽

Sound Power ◽

Mean Square ◽

Sound Power Level ◽

Measuring Surface ◽

Underwater Structure ◽

Acoustical Holography

This paper analyzes the effects of the swinging NAH(Near field Acoustical Holography) measuring array on measurement of the sound power level of underwater structure. We use the method of sound intensity integral, the method of mean square sound pressure and the method of NAH reversal pressure to calculate the sound power level under certain collection of frequency with measuring surface in different states. We also analyze the relative error of results acquired by those methods, which can help validating the reliability and the error estimate of the results calculated with NAH.

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