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Generation, Propagation, and Reduction of Aerodynamic Broadband Noise from Wind Turbines : 풍력터빈에서 발생하는 광대역 소음의 생성과 전파 및 저감에 대한 연구

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dc.contributor.advisor이수갑-
dc.contributor.author이승훈-
dc.date.accessioned2017-07-13T06:16:37Z-
dc.date.available2017-07-13T06:16:37Z-
dc.date.issued2014-08-
dc.identifier.other000000021730-
dc.identifier.urihttps://hdl.handle.net/10371/118411-
dc.description학위논문 (박사)-- 서울대학교 대학원 : 기계항공공학부, 2014. 8. 이수갑.-
dc.description.abstractAerodynamic broadband noise generated from horizontal axis wind turbines is investigated in this research. First, a numerical method to predict wind turbine aerodynamic noise is proposed by using an analytic trailing edge noise model and a wall-pressure spectral model for flow with adverse pressure gradient. Reynolds-averaged Navier-Stokes simulation and XFOIL code are used to obtain the wall-point pressure spectra at blade sections. This method is fast and reliable numerical model which is applicable for use in industrial applications. For the validation of the numerical method, noise measurement is also carried out for a 10kW wind turbine, and a comparison is made between the predicted results and the measured data. Using the proposed method, the aerodynamic noise from a 3MW wind turbine is predicted at various inflow wind speeds and distances. Moreover, time domain simulation for the wind turbine aerodynamic noise is performed to examine the main cause of the amplitude modulation of wind turbine noise, as well as to compare the acoustical characteristics depending on the observer locations. Analytic trailing edge noise and turbulence ingestion noise models are used to determine the unsteady pressure on the blade surface. The far-field acoustic pressure due to the unsteady pressure is calculated using the acoustic analogy theory. By using a strip theory approach, the two-dimensional noise model is applied to rotating wind turbine blades. The numerical results indicate that, although the operating and atmospheric conditions are identical, the acoustical characteristics of wind turbine noise can be quite different with respect to the distance and direction from the wind turbine. Using these prediction results, it is investigated why the amplitude modulation of wind turbine noise is heard even at long distances from a wind turbine. Furthermore, to reduce trailing edge noise from a 10kW wind turbine, the airfoil shape and the planform of the wind turbine blade are modified using optimization techniques based on genetic algorithms. The optimized airfoil is first determined based on a section of the rotor blade, and then the optimized blade is designed with this airfoil. A wind tunnel experiment is also performed to validate the design optimization. In addition, wind turbine blades with serrated trailing edge are also examined for the noise reduction. To examine the effect of serrated trailing edge on the trailing edge noise reduction, a field experiment is carried out based on a 10kW wind turbine.-
dc.description.tableofcontents1. Introduction 1
1.1. Wind turbine aerodynamic noise 1
1.2. Current issues 4
1.3. Research objective 7

2. A prediction model for wind turbine noise 9
2.1. Overview of wind turbine prediction models 9
2.2. Numerical method 12
2.2.1. Trailing edge noise model 12
2.2.2. Turbulence ingestion noise model 16
2.2.3. Trailing edge bluntness noise model 17
2.2.4. Wall-pressure spectral model 18
2.3. Model validation 19
2.3.1. Wall-point pressure spectrum with RANS simulation and XFOIL 19
2.3.2. Trailing edge noise 30
2.3.3. Wind turbine aerodynamic noise 33
2.3.3.1. Noise measurement 33
2.3.3.2. Results 36
2.4. Results 39
2.4.1. Wind turbine model 39
2.4.2. Aerodynamic analysis 41
2.4.3. Noise prediction 43
2.5. Discussion 48

3. Time domain simulation of wind turbine noise 50
3.1. Introduction 50
3.1.1. Amplitude modulation of wind turbine noise 50
3.1.2. Literature review 53
3.1.3. Research objective 55
3.2. Numerical method 57
3.2.1. Trailing edge noise model 57
3.2.2. Turbulence ingestion noise model 59
3.2.3. Acoustic formulation 61
3.2.4. Validation 63
3.2.4.1. Trailing edge noise 63
3.2.4.2. Turbulence ingestion noise 66
3.2.5. Calculation case 69
3.2.5.1. Rotor noise prediction 69
3.2.5.2. Calculation cases 71
3.3. Results 73
3.3.1. Case I—Uniform inflow 73
3.3.1.1. IEC 61400-11 reference position 73
3.3.1.2. Noise characteristics with respect to distance and direction 75
3.3.1.3. Noise source distribution 78
3.3.1.4. Noise index for the amplitude modulation of wind turbine noise 81
3.3.2. Case II—Stationary in motion 84
3.3.3. Case III—Vertical wind shear 86
3.3.4. Case IV—Turbulence ingestion 90
3.4. Discussion 95

4. Wind turbine noise reduction techniques 100
4.1. Introduction 100
4.2. Design optimization of airfoil and blade planform 102
4.2.1. Airfoil design optimization 102
4.2.1.1. Airfoil optimization procedure 102
4.2.1.2. Airfoil optimization result 106
4.2.2. Blade design optimization 109
4.2.2.1. Blade optimization procedure 109
4.2.2.2. Blade optimization result 111
4.2.3. Experimental results and discussion 113
4.3. Serrated trailing edge blade 117
4.3.1. Experimental setup 117
4.3.2. Results and discussion 121

5. Conclusions 127
References 129
국문 초록 138		-
dc.formatapplication/pdf-
dc.format.extent12406255 bytes-
dc.format.mediumapplication/pdf-
dc.language.isoen-
dc.publisher서울대학교 대학원-
dc.subjectWind turbine noise-
dc.subjectNoise reduction-
dc.subjectTrailing edge noise-
dc.subjectTurbulence ingestion noise-
dc.subjectDesign optimization-
dc.subjectNoise measurement-
dc.subject.ddc621-
dc.titleGeneration, Propagation, and Reduction of Aerodynamic Broadband Noise from Wind Turbines-
dc.title.alternative풍력터빈에서 발생하는 광대역 소음의 생성과 전파 및 저감에 대한 연구-
dc.typeThesis-
dc.contributor.AlternativeAuthorLee, Seunghoon-
dc.description.degreeDoctor-
dc.citation.pagesxix, 139-
dc.contributor.affiliation공과대학 기계항공공학부-
dc.date.awarded2014-08-
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