J0503-4-2 A study on aerodynamic noise characteristics by wind turbine blade reforming

The purpose of this research is to investigate the physical mechanisms associated with broadband tip vortex noise caused by rotating wind turbines. The flow and acoustic field around a wind turbine blade is simulated using compressible large-eddy simulation and direct noise simulation, with emphasis on the blade tip region. The far field aerodynamic noise is modeled using acoustic analogy. Aerodynamic performance and acoustic emissions are predicted for the actual tip shape and an ogee type tip shape. For the ogee type tip shape the sound pressure level decreases by 5 dB for frequencies above 4 kHz.

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Diagnosis of damaged wind turbine blade by noise characteristics

Noise Control Engineering Journal ◽

10.3397/1/376813 ◽

2020 ◽

Vol 68 (2) ◽

pp. 146-156

Author(s):

Chao-Nan Wang ◽

Tang-Yao Chi

Keyword(s):

Feature Extraction ◽

Wind Turbine ◽

Turbine Blade ◽

Frequency Analysis ◽

Time Domain ◽

Wind Turbine Blade ◽

Statistical Regression ◽

Time Frequency Analysis ◽

Time Frequency ◽

Noise Characteristics

This study has proposed two estimation models of noise signal characteristic diagnosis based on time-domain and time-frequency analysis. The diagnosis of time domain was based on the fractal theory, and the result of fractal dimensions was converted into Gauss distribution, so as to provide a feature extraction for abnormality diagnosis of damaged blade. In addition, for time-frequency analysis, the wavelet methodwas used as the basis of signal analysis. The Morlet transform and mother wavelet were used for wavelet analysis of signal to obtain the result of time-frequency analysis. When the time axis was integrated, the marginal spectrum of frequency domain was obtained, and statistical regression analysis was used to provide another method of feature extraction diagnosis. The wind turbine blade signal was measured in actual wind turbine operation at Changhua Coastal Industrial Park for diagnostic analysis, so as to provide a multi-diagnostic model of wind turbine blade prewarning and health management models.

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219 An experimental study on aerodynamic noise from wind turbine blade : Noise reduction and lift drag ratio of the blade

The Proceedings of Conference of Tohoku Branch ◽

10.1299/jsmeth.2008.43.239 ◽

2008 ◽

Vol 2008.43 (0) ◽

pp. 239-240

Author(s):

Toshiaki MINOWA ◽

Hideki ONODERA

Keyword(s):

Experimental Study ◽

Wind Turbine ◽

Noise Reduction ◽

Turbine Blade ◽

Wind Turbine Blade ◽

Aerodynamic Noise ◽

Drag Ratio

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Aeroacoustics Simulation Around a Wind Turbine Blade Using Compressible LES and Linearized Euler Equations

Volume 1: Fora, Parts A, B, C, and D ◽

10.1115/fedsm2003-45368 ◽

2003 ◽

Author(s):

Oliver Fleig ◽

Chuichi Arakawa

Keyword(s):

Wind Turbine ◽

Euler Equations ◽

Turbine Blade ◽

Acoustic Waves ◽

Separated Flow ◽

Wind Turbine Blade ◽

Large Region ◽

Aerodynamic Noise ◽

Far Field ◽

Linearized Euler Equations

There is a strong need to investigate aerodynamic noise caused by large and fast rotating wind turbines, especially trailing edge and tip noise. This work constitutes the first part of a project which aims to simulate the broadband tip noise emitted when the wind turbine is in operation. Several aeroacoustics methods are analyzed and their suitability for a typical wind turbine blade is assessed. A stationary wind turbine blade in an incident flow with a large region of separated flow is studied. The surface pressure fluctuations are calculated using compressible Large-Eddy simulation (LES). The aerodynamic noise perceived in the far-field is predicted by simulating the propagation of the pressure perturbations using LES and Linearized Euler equations (LEE) in the near field and Kirchhoff’s integral method in the far-field. It was found that for the present wind turbine blade with a large region of separated flow and thus relatively large fluctuations, LES with a fine enough mesh and a third-order upwind scheme is able to compute the propagation of acoustic waves as accurately as LEE with higher order schemes and separate treatment of acoustic perturbations. The method described in this paper will be used in the future to analyze a full wind turbine blade with the aim of optimizing the tip shape for reduced noise emission.

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