scholarly journals Wind turbine sound power measurements

2016 ◽  
Vol 139 (3) ◽  
pp. 1431-1435 ◽  
Author(s):  
Stephen E. Keith ◽  
Katya Feder ◽  
Sonia A. Voicescu ◽  
Victor Soukhovtsev ◽  
Allison Denning ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Sound Power ◽  
Power Measurements

Sound power and sound energy measurements using an ellipsoidal measurement surface

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.

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

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

The Effect of Room Characteristics on Sound Power Measurements

Noise Control ◽  
1959 ◽  
Vol 5 (1) ◽  
pp. 59-77 ◽  
Author(s):  
R. W. Benson ◽  
R. Huntley
Keyword(s):  
Sound Power ◽  
Power Measurements

scholarly journals Acoustic Emissions from Wind Turbine Blades

2019 ◽  
Author(s):  
Vasishta Bhargava ◽  
Rahul Samala
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Power Level ◽  
Turbine Blades ◽  
Acoustic Emissions ◽  
Aerodynamic Noise ◽  
Sound Power ◽  
Wind Turbine Blades ◽  
Blade Length ◽  
Noise Production

Research on broadband aerodynamic noise from wind turbine blades is becoming important in several countries. In this work, computer simulation of acoustic emissions from wind turbine blades are predicted using quasi empirical model for a three-bladed horizontal axis 3 MW turbine with blade length ~47 m. Sound power levels are investigated for source and receiver height of 80 m and 2 m above ground and located at a distance equal to total turbine height. The results are validated using existing experimental data for Siemens SWT-2.3 MW turbine having blade length of 47 m, as well as with 2.5 MW turbine. Aerofoil self-noise mechanisms are discussed in present work and results are demonstrated for wind speed of 8 m/s. Overall sound power levels for 3 MW turbine showed good agreements with the existing experiment data obtained for SWT-2.3 MW turbine. Noise map of single source sound power level, dBA of an isolated blade segment located at 75 %R for single blade is illustrated for wind speed of 8 m/s. The results demonstrated that most of the noise production occurred from outboard section of blade and for blade azimuth positions between 80° and 170°.

scholarly journals Trailing Edge Thickness Effect on Tonal Noise Emission Characteristics from Wind Turbine Blades

2021 ◽  
Vol 13 (4) ◽  
pp. 99-111
Author(s):  
Satya Prasad MADDULA ◽  
Vasishta Bhargava NUKALA ◽  
Venkata Swamy Naidu NEIGAPULA
Keyword(s):  
Wind Turbine ◽  
Power Level ◽  
Turbine Blades ◽  
Broadband Noise ◽  
Thickness Effect ◽  
Sound Power ◽  
Noise Generation ◽  
Wind Turbine Blades ◽  
Trailing Edge ◽  
Sound Power Level

Broadband noise generation from wind turbine blades is one of the fundamental aspects of flow-induced noise. Besides the turbulent boundary layer flow over the blades, factors such as the angle of attack, the turbulence intensity, the trailing edge thickness of the blade and their shapes strongly influence the overall sound power levels at high frequencies, i.e. f > 8 kHz. In large operating wind farms, a trade-off between noise generation and power production is considered by power utility firms to maximize the return on investment (ROI) and minimize the fatigue damage on wind turbine components. The present work deals with the analysis of the thickness effect on trailing edge bluntness noise level at hub height average wind speeds of 7 m/s, 10 m/s. A semi-empirical BPM model was used to predict the sound pressure levels from the 37 m blade length of a 2MW wind turbine. The receiver configuration was fixed at a distance of 120 m from the source height of 80 m. The results demonstrated that as the trailing edge height increased from 0.1 % to 0.5 % of the local chord, the sound power level increased by ~ 17 dB for frequencies > 200 Hz, but decreased by 16 dB when the thickness is 0.1 % local chord. The computed results of the sound power level using the BPM model have been validated using experimental data and showed a good agreement for the tonal frequencies, f ~ 10 kHz, where the trailing edge bluntness noise becomes dominant.

The relative variance in sound power measurements using reverberation rooms

1989 ◽  
Vol 128 (1) ◽  
pp. 57-69 ◽  
Author(s):  
M. Tohyama ◽  
A. Imai ◽  
H. Tachibana
Keyword(s):  
Sound Power ◽  
Relative Variance ◽  
Power Measurements
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