CHARACTERIZATION OF TRAILING EDGE BROADBAND NOISE FROM WIND TURBINE BLADES

2021 ◽  
Vol 263 (6) ◽  
pp. 42-53
Author(s):  
Satya Prasad Maddula ◽  
Vasishta Bhargava ◽  
Naidu N.V. Swamy
Keyword(s):  
Wind Turbine ◽  
Power Level ◽  
Turbine Blades ◽  
Critical Issue ◽  
Sound Level ◽  
Broadband Noise ◽  
Present Approach ◽  
Trailing Edge ◽  
High Frequencies ◽  
Regression Approach

Wind turbine noise is a critical issue for siting and its operation in offshore and terrestrial conditions. In this work, we analysed trailing edge bluntness vortex shedding noise source for a land based turbine of size 2MW and blade span of 38m using modified BPM noise solver. A regression approach has been implemented to predict the shape function in terms of thickness to chord ratio of aerofoils used for blade. For trailing edge height of 1 % chord, computations for sound power level were done at wind speed of 8m/s, 17 RPM, and showed that present regression approach predicts the noise peak of 78dBA at f ~ 10 kHz. These results were also validated using experiment data from GE 1.5sle, Siemens 2.3MW turbines with blade lengths of 78 -101m and agreed within 2 % at very high frequencies, f > 5kHz. In addition, results from present approach agreed with original BPM and modified BPM by Wei et al at high frequencies, f ~ 10kHz where the bluntness noise becomes predominant. The slope of noise curves from present approach, and modified BPM methods are lower when compared with original BPM and show sound level coincidence with peak Strouhal number of ~ 3.3.

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.

Selection of a leading edge noise prediction method for PNoise

2018 ◽  
pp. 214-223
Author(s):  
AM Faria ◽  
MM Pimenta ◽  
JY Saab Jr. ◽  
S Rodriguez
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Prediction Method ◽  
Leading Edge ◽  
Wind Farms ◽  
Broadband Noise ◽  
Turbulence Energy ◽  
Noise Prediction ◽  
Migration Routes ◽  
Turbulent Inflow

Wind energy expansion is worldwide followed by various limitations, i.e. land availability, the NIMBY (not in my backyard) attitude, interference on birds migration routes and so on. This undeniable expansion is pushing wind farms near populated areas throughout the years, where noise regulation is more stringent. That demands solutions for the wind turbine (WT) industry, in order to produce quieter WT units. Focusing in the subject of airfoil noise prediction, it can help the assessment and design of quieter wind turbine blades. Considering the airfoil noise as a composition of many sound sources, and in light of the fact that the main noise production mechanisms are the airfoil self-noise and the turbulent inflow (TI) noise, this work is concentrated on the latter. TI noise is classified as an interaction noise, produced by the turbulent inflow, incident on the airfoil leading edge (LE). Theoretical and semi-empirical methods for the TI noise prediction are already available, based on Amiet’s broadband noise theory. Analysis of many TI noise prediction methods is provided by this work in the literature review, as well as the turbulence energy spectrum modeling. This is then followed by comparison of the most reliable TI noise methodologies, qualitatively and quantitatively, with the error estimation, compared to the Ffowcs Williams-Hawkings solution for computational aeroacoustics. Basis for integration of airfoil inflow noise prediction into a wind turbine noise prediction code is the final goal of this work.

Analysis of Blunt Trailing Edge Airfoils

2003 ◽  
Author(s):  
K. J. Standish ◽  
C. P. van Dam
Keyword(s):  
Experimental Data ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Navier Stokes ◽  
Computational Techniques ◽  
Wind Turbine Blades ◽  
Trailing Edge ◽  
Blunt Trailing Edge ◽  
Large Wind ◽  
Structural Volume

The adoption of blunt trailing edge airfoils for the inner regions of large wind turbine blades has been proposed. Blunt trailing edge airfoils would not only provide increased structural volume, but have also been found to improve the lift characteristics of airfoils and therefore allow for section shapes with a greater maximum thickness. Limited experimental data makes it difficult for wind turbine designers to consider and conduct tradeoff studies using these section shapes. This lack of experimental data precipitated the present analysis of blunt trailing edge airfoils using computational fluid dynamics. Several computational techniques are applied including a viscous/inviscid interaction method and several Reynolds-averaged Navier-Stokes methods.

Trailing edge noise reduction of wind turbine blades by active flow control

Wind Energy ◽  
2014 ◽  
Vol 18 (5) ◽  
pp. 909-923 ◽  
Author(s):  
Alexander Wolf ◽  
Thorsten Lutz ◽  
Werner Würz ◽  
Ewald Krämer ◽  
Oksana Stalnov ◽  
...  
Keyword(s):  
Flow Control ◽  
Wind Turbine ◽  
Noise Reduction ◽  
Active Flow Control ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Trailing Edge ◽  
Trailing Edge Noise ◽  
Active Flow

Fatigue Failure of a Composite Wind Turbine Blade at the Trailing Edge

2018 ◽  
Vol 382 ◽  
pp. 191-195 ◽  
Author(s):  
Zu Jin Pan ◽  
Jian Zhong Wu ◽  
Jian Liu ◽  
Xin Hua Zhao
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Failure Modes ◽  
Fatigue Testing ◽  
Turbine Blades ◽  
Local Stress ◽  
Wind Turbine Blade ◽  
Trailing Edge ◽  
Balsa Wood ◽  
Abnormal Sound

The downtime problem of wind turbine increases due to fatigue damage of wind turbine blades, which is even more crucial in the larger blades. One of the critical failure modes is the blade trailing edge failure, which can result in the trailing edge joint cracked. In this paper, we experienced that abnormal sound was happened in the trailing edge at the cross-section in the max chord during fatigue testing of a 2 MW full-scale wind turbine blade according to IEC61400-23. Through the conditional monitoring of the trailing edge, the delamination between GFRP and balsa wood is caused by stress concentration. The abnormal sound is happened due to GFRP beat the balsa wood when the blade vibrates in the edgewise direction. Moreover, the sound is amplified because the introduction of air due to the delamination. The local stress distribution and stability factors are computed through FEM methods, the program that increasing the core materials in the trailing edge is proposed. Therefore the structure reliability in the trailing edge is improved.

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 subcomponent testing for wind turbine blades–Part A: Comparison of concepts

Wind Energy ◽  
2019 ◽  
Vol 22 (4) ◽  
pp. 487-498 ◽  
Author(s):  
M. Rosemeier ◽  
A. Antoniou ◽  
X. Chen ◽  
F. Lahuerta ◽  
P. Berring ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Trailing Edge
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