Sound Power Comparison Based on Sound Pressure and Sound Intensity

2010 ◽  
Author(s):  
Marlon Casagrande Rodrigues ◽  
Alexandre Barcelos de Souza ◽  
Georges Vretos Glyniadakis ◽  
Mauro Miguel Pecula
Keyword(s):  
Sound Pressure ◽  
Sound Intensity ◽  
Sound Power ◽  
Power Comparison

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

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

Sound Power Measurements in the Near Field of Transformers

2012 ◽  
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.

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

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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