Experimental and numerical validation of vibration-based sound power measurements of arbitrarily curved panels

Trent P. Bates; Ian C. Bacon; Scott D. Sommerfeldt; Jonathan D. Blotter

doi:10.1121/10.0008529

Experimental and numerical validation of vibration-based sound power measurements of arbitrarily curved panels

The Journal of the Acoustical Society of America ◽

10.1121/10.0008529 ◽

2021 ◽

Vol 150 (4) ◽

pp. A344-A344

Author(s):

Trent P. Bates ◽

Ian C. Bacon ◽

Scott D. Sommerfeldt ◽

Jonathan D. Blotter

Keyword(s):

Sound Power ◽

Numerical Validation ◽

Power Measurements ◽

Curved Panels

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Sound power and sound energy measurements using an ellipsoidal measurement surface

INTER-NOISE and NOISE-CON Congress and Conference Proceedings ◽

10.3397/in-2021-2246 ◽

2021 ◽

Vol 263 (4) ◽

pp. 2863-2874

Author(s):

Edward Zechmann

Keyword(s):

Free Field ◽

Field Approximation ◽

Global Scale ◽

Low Noise ◽

Sound Power ◽

Wave Propagation Direction ◽

Sound Energy ◽

Alternative Approach ◽

Measurement Surface ◽

Power Measurements

To support purchasing low noise products, sound power and sound energy measurements of sufficient quality need to be routinely made by consumers on a global scale. Sound power measurements using ISO 3744, 3745, and 3746 are conducted in a free field using an acoustic far-field approximation of the intensity integrated over an enveloping measurement surface. Sound power and sound energy measurements generally use a hemispherical, parallelepiped, or cylindrical measurement surface. Those measurement surfaces have limitations and assume that the measurement points lie on the measurement surface often in preferred positions. An alternative approach is to choose microphone positions that optimally satisfy the assumptions of the measurement. The measurement surface should then be fit to the chosen microphone positions. Regression methodologies are available for fitting ellipsoids. The number of microphone positions can be as few as three to fit an ellipsoid. An ellipsoidal measurement surfaces can abut zero, one, two, or three orthogonal reflecting planes. Correction equations for the microphone locations and the angle errors for the microphone orientation and wave propagation direction are shown. This paper will present simulations of sound power, sound energy, and corrections for environmental reflections for ISO 3745 and other measurement surfaces.

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