k

593

Index

1/3-octave band 83 atmospheric boundary layer 128 3-D terrain modelling 564 blade tip 129 separation 130 A-weighting 72 tip 130 filter coefficients 314 tower 128 Accelerometer 394 trailing edge 130 calibration 394 Aerodynamic noise 119 Acoustic holography 505 control 477 Active noise control 488, 506 prediction 160 control filter 489, 490 trip 120 k control loudspeakers 489 Airfoil k feedforward control 488 angleofattack 120 gradient descent algorithm 590 deep stall 121 MIMO system 590 lift 139 reference microphones 489 self-noise 160 SISO system 588 separation 120 Active pitch control 505 separation bubble 136 Active stall control 3 separation point 121 Addition of decibels 69 stall 120 Adverse health effects 436, 439 Aliasing 103 case studies 451 Amplitude 60 criteria 452 Amplitude correction factor 98 exposure duration 448 Amplitude modulation 66, 329, 453, 454, infrasound 448 481, 500 laboratory studies 465 COPYRIGHTEDD AMMATERIAL332 motion sickness 464 analysis bandwidth 344 nausea 464 causes 330 seasickness 450 consensus 341 sensitisation 452, 464 Den Brook condition 20 332 symptoms 452 detection 341, 342 vibration 467 disadvantages of various methods 343 Aero-elastic response 148 Hilbert transform 332 Aeroacoustic excitation 477 Hybrid method 1 338 Aerodynamic environment 128, 130 Hybrid method 2 339

Wind Farm Noise: Measurement, Assessment and Control, First Edition. Colin H. Hansen, Con J. Doolan, Kristy L. Hansen. © 2017 John Wiley & Sons Ltd. Published 2017 by John Wiley & Sons Ltd.

k k

594 Index

Amplitude modulation (contd.) fixed blade testing 422 Lee method 336 full-scale wind turbine 424 Lenchine method 341 high-frequency limit 419 Lundmark method 338 low-frequency 425 measurement 330, 331 low-frequency limit 419 metrics 331, 332 measurements 423 modulation depth 455 microphone mounting 421 Nordtest method 340 point-spread function 419 quantification 455 practical issues 421 RES/RUK methods 337 resolution 418, 419 Amplitude spectrum sound maps 418 scaling factor 98 uncertainty analysis 421 Amplitude variation 67, 345, 454, 500 Beating 64, 329, 453, 501 Anemometer positioning 399 BEMT theory 160, 163 Angle of attack 120 Bias error 99 Annoyance 442, 445 Binary files 296 threshold, low-frequency noise 460 Blackman window 100 Anti-aliasing filter 82 Blackman–Harris window 100 Antinodes 76 Blade Aperture size 419 chord 120 Arc length 204 design 478 AS4959 (2010) 31 stall 481 k Assessment procedures 18 twist 481 k Atmospheric Blade–tower interaction 14, 145, 482, 505 absorption 186 Blade–vortex interaction 140 boundary layer 128 Blade-element-momentum theory 160 stability 404 Blade-pitch control 481 temperature profile 196 Blunt airfoil 136 turbulence 189 Blunt trailing-edge noise 166 turbulence measurement 395 model 513 Audio range 459 BPM Auto power spectrum 91, 92 amplitude function 511 Auto-correlation function 113 model 163–165, 509 spectral shape 511 Background noise BTI noise 145–147 measurement 308, 311 Byte 296 regression analysis 312 Balloon systems 399 C-weighting 72 Bark scale 319, 350 filter coefficients 314 Battery 298 Capacity factor 4 charge controller 299 Central moment 59 Beamforming 141, 386, 415, 417, 420, 504 Characteristic impedance 518 aperture size 419 Characteristic velocity 125 beamwidth 419 Chord 162 CLEAN algorithm 420 Circular convolution 112 CLEAN-SC 420 CNEL 76 deconvolution 419, 420 Cochlea 457

k k

Index 595

central partition 457 ground effects 215 length 457 in-plant screening 221 Cochlear duct 457 input data 269 Coherence 109 limitations 221 Coherent addition 244 meteorological effects 215 Coherent output power 111 source-height effects 218 Compact source 136, 142 spherical spreading 214 Complex compressibility 519 terrain shielding 220 Complex conjugate 508 uncertainty 272 Complex density 519 vegetation screening 221 Complex number 508 Condenser microphone 291 trigonometric form 508 Controlofnoise 476 Compliance Convective amplification 131, 132 AM 372 Convolution 112 assessment 291, 310, 503 Cooling fan noise 150 Australian standard 367, 368 Crest factor 58, 84 background noise 370 Critical bands 318 data filtering 370 Bark 318 downwind data 370 Critical bandwidth 86, 319 ETSU guidelines 367 Critical-band rate 350 limit exceedance 370 Cross-correlation function 113 New Zealand standard 367, 368 Cross-spectral density 108 k nighttime data 370 Cross-spectrum 107, 108 k on/off testing 370 single-sided 108 seasonal variations 370 two-sided 108 tonality 352 Cup anemometer 395, 396 Compliance methodologies 369 friction 396 improvements 370 Curle 125 Compliance testing 35, 365, 381 Current measurement 298 1/3-octave band analysis 379 alternative methods 373 Data storage 310 background noise subtraction 374 Decibel addition 69 bin analysis 379 Decibel subtraction 70 exceedance time percent 382 Deconvolution 112 extraneous noise 377 Deep stall 121, 139 improvements 372 DEFRA guidelines 27 instrumentation 37 Density limited wind speed range 379 air 63 statistical analysis 381 Design modulation depth 347 summary 384 Detached eddy simulation 169 Compressibility 519 Detrend 337 Compressible fluid 125 DFT 80 Computational fluid dynamics modelling Diffraction wedge 582 163 Digital filter 82 CONCAWE model 214 Digital sampling 59 atmospheric absorption 214 Dipole 121, 127 barrier attenuation 218 source 147

k k

596 Index

Dirac delta function 125 quadrupole 127 Direct-drive wind turbine 151 thickness 127 Directivity 71 FFT 80, 335 reflecting plane 71 analysis 88 Discrete Fourier transform 80 Filter DNL 76 bandwidth, minimum 84 Double-edge diffraction 227 rise time 86 Downwind refraction 189 rise time, octave band 84 settling time 88 EAM 453 Fixed blade testing 422 Ear canal 455 Flat-top window 102 Ear infection 457 Flow resistivity 517 Eardrum 455 Fluctuation strength 349, 350 Effects on people 436, 496 amplitude modulated tonal noise 350 Einstein’s summation 125 Flutter 148 Enhanced amplitude modulation 144, 147, Fourier analysis 80 453, 505 Frequency 61 Envelope analysis 106 Frequency analysis 88 Envelope signal 67 aliasing 103 Epidemiological study 498 amplitude correction factor 98 Equal loudness curves bias error 99 infrasound 460 Blackman window 100 k Equalise 466 Blackman–Harris window 100 k Equivalent continuous sound pressure level coherence 109 74 complex spectral amplitude 89 Equivalent wedge 570 error 97 Error function 522 exponential window 101 ETSU-R-97 18 flat-top window 97, 102 Excess attenuation 181, 183 Gaussian window 101 atmospheric absorption 186 Hamming window 100 ground effect 187 Hanning window 102 line of sources 184 Kaiser–Bessel window 101 meteorological effects 188 overlap processing 103 spherical spreading 183 Poisson window 101 Excessive amplitude modulation 481 random noise 90 Expanded uncertainty 393 rectangular window 98 Exponential function 508 scaled spectrum 98 Exponential window 101 side lobes 97 External ear 455 triangular window 100 Extraneous noise 501 uncertainty principle 105 sources 309 Welch window 102 windowing 96 Fast response 295 zero padding 105 Ffowcs Williams 125 Frequency resolution 91 Ffowcs-Williams–Hawkings 126, 149 Frequency spectrum 80 equations 169 Frequency-response function 110 loading 127 Fresnel ellipsoid 566

k k

Index 597

Fresnel parameter 566 frequency band averaging 263 Fresnel weight 581, 587 Fresnel weighting 580, 586 barrier 568 Fresnel zone 564, 584 frequency dependent 568 geometrical weighting factor 581 segmented terrain 567 ground between diffraction edges Fresnel zone 564 582 area 566 ground effect 572, 577 barrier 570 ground, terrain and barriers 264 convex ground 570 input data 271 equivalent wedge 570 limitations 268 reflection from flat ground 564 meteorological effects 265 sonic gradient 566 modified Fresnel weight 581 Fringe: leading edge 480 reflection from vertical surface 267 scattering 266 G-weighting 72 spherical spreading 261 filter coefficients 317 transition model 582 Gaussian window 101 turbulence 263, 264, 267 Gearbox uncertainty 263, 273 design 150 Hawkings 147 noise 150, 477, 486, 505 Health effects 436 Generator noise 150 infrasound 438 Good Neighbour Agreement 437 low-frequency noise 443 k Good Practice Guide 21 physiological link 498 k Government inquiries surveys 437 Australia 43 Hearing Canada 48 frequency range 459 Denmark 50 infrasound 450, 459, 462 Northern Ireland 51 mechanism 455, 459 Scotland 51 threshold 62, 450, 454, 461 Wales 51 Helicotrema 457 Guidelines 18 Helmholtz resonance 324 Hilbert transform 107, 332 Hair cells 459 Homogeneous atmosphere 232 stereocilia 459 Hydrops 448 Hamming window 100 Hanning window 96, 100 IEC 61400-11 (2012) 29 Harmonoise propagation model 260, Impulse response 84, 110, 295 572 Impulsive noise 14, 16 atmospheric absorption 261 In-plant screening 221 coherence coefficients 263 Incoherent reflection coefficient 524 coherence effects 263 Incus 456 coherence factor 581 Indoor noise 322 combining sound rays 263 Danish guideline 322 concave ground model 579 level 276 convex hull 577 measurement 327 coordinate transformation 265 standing waves 322 diffraction effect 572, 574 Swedish procedure 323

k k

598 Index

Inflow Levening 76 angle 161 Lnight 76 noise 141 Laminar flow 120 turbulence noise 141 Leakage 95 Infrasound 210, 438, 441 LES modelling 163 control 476 LIDAR 398 Inner ear 457 Light stall 139 Instability, tonal noise 136 Lighthill 122, 124, 125 Installed capacity 8 Linear sound-speed gradient 528 Instrumentation Linear spectrum 95 battery 298 Local induction factor 161 data storage 310 Local solidity 162 noise floor 310, 503 Logarithm 507 power requirements 298 Logarithmic velocity profile 191 recording 294 Loudness 62, 350 solar panels 298 Low-frequency guidelines Interior noise level measurement 277 Danish 499 IOA Good Practice Guide 21 DEFRA 499 problems 24 Japanese 499 supplementary notes 22 Low-frequency noise 210 ISO9613-2 propagation model 223 attenuation 446 adjustments for wind farm noise control 476 k 228 Low-level jets 209 k

attenuation component, Amisc 223 LSL weighting 442 barrier attenuation 225 double-edge diffraction 227 Méniére’s disease 448 ground effects 224 Mach number 121 input data 269 Machinery noise sources 149 limitations 230 Malleus 456 reflections 228 Masking 492, 506 uncertainty 273 depth 350 vegetation screening 227 Maximum height 198 Measurement 290 Kaiser–Bessel window 101 A-weighted values 314 Kolmogorov scale 122 amplitude modulation 329 Kurtosis 60 background noise 308 normal distribution 60 C-weighted values 314 indoor noise 322, 327

LA50 75 infrasound 317 LA90 75 low-frequency noise 317 LA90,10min 19 outdoor-to-indoor noise reduction 324, LAeq 75 326 LAeq,10min 19 reporting 405–408 Lday 76 special audible characteristics 291 Lden 76 wind speed 395 Ldn 76 wind tunnel testing 408 Leq 74 Measurement uncertainty 387

k k

Index 599

1/3-octave filter 390 Middle ear 455 calibrator 389 MLS estimation 391 excitation 115 expanded uncertainty 393 sequence 116 position of the microphone 388 Modal response 77 reflective surfaces 389 Modulation seasonal variations 391 depth 347 sound level meter 389 factor 349 sources 387 Monopole 121, 127 standard uncertainty 393 Multiple ground reflections 207 type A estimation 391 number of 209 type B estimation 392 wind screen influence 388 Nacelle anemometer 400 wind-induced noise 388 National Health and Medical Research windowing data 390 Council 497 Mechanical noise 477 National Planning Policy Framework 25 Meteorological data measurement Navier–Stokes equations 163, 169 403 Neutral atmosphere 232 Meteorological mast 399 NHMRC 497 disadvantages 400 NMPB-2008 model 231, 504 Meteorological tower 396 diffraction with no ground effect 236 Metric ground effect plus diffraction 239 k annoyance assessment 442 ground effect, no diffraction 234 k Microbarometer 317 ground, barrier, terrain effects 232 Microphone input data 270 calibration 296 limitations 242 diaphragm 292 mean ground plane 233 electret 291 reflection from vertical surface 241 electrical noise 293 vertical edge diffraction 241 equalisation 297 Nocebo effect 1, 467 externally polarised 292 Nodes 76 fence enclosure 305 Noise free-field response 292 bandwidth 97 frequency response 291 definition 57 measurement height 307 descriptors, statistical 59 mounting 301 Perception Index 28 noise floor 296 psychoacoustic descriptors 349 pre-amplifier 293 Noise control 476 prepolarised electret 292 active system indoors 488 primary wind screen 306 aeroacoustic excitation 485 underground box 307 blade design 478 wind screen 301 blade–tower interaction 482 wind screen insertion loss 306 efficient blade design 482 wind-induced noise 301 gearbox noise 486 wind-induced noise reduction 305 leading edge fringe 480 Microphone array 304, 415, 423 masking 492 Microphone calibrator 297 owl wing 479

k k

600 Index

Noise control (contd.) ground plus single diffraction 557 phase control 483 ground, terrain and barrier effects pitch reduction 482 249 poro-elastic TE 479 incoherence effects 245 quieter blade design 478 input data 271 residences 488 limitations 259 serrated trailing edge 480 multiple ground reflections 252 shutting down turbines 492 reflection from a vertical surface 256 soft downy coating 481 refraction fluctuations 246 thumping noise 481 scattering attenuation 255 trailing-edge treatment 479 scattering by forests 248 tuned mass dampers 486 segmented terrain profile 539 vibration absorbers 486 single wedge diffraction 548 wind farm layout 487 spherical spreading 243 Noise ordinances 38 surface roughness 248 Noise propagation models see terrain effects 534 Propagation models180 transition ground segment 536 Noise regulations 32, 38 turbulence 247 compliance testing 35 two diffraction edges 550 what should be included 32 two finite-impedance wedges 554 Noise source identification 504 uncertainty 273 beamforming 504 valley-shaped terrain 536 k Noise standards 29 vertical surface reflection 537 k ANSI 12.9-4 (2005) 29 Normalised frequency 97 AS4959 (2010) 31 Normalised sound-speed gradient 530 IEC 61400-11 (2012) 29 NPI 28 ISO 1996 29 Nyquist frequency 82 ISO1996-1971 30, 33 NZS6808 (2010) 31 NZS6808 (2010) 31 Non-compact source 142 Octave band 83 Nord2000 propagation model 242 Omni-directional 71 atmospheric absorption 243 One-third octave band 83 atmospheric effects 249 Order tracking 106, 362, 364 combining different rays 244 Ordinances 38 concave ground 536 Ossicles 456 convex ground 536 Outdoor sound propagation 190, 194 diffraction effect 544, 547 Outdoor-to-indoor noise downward-refracting atmosphere measurement 324, 326 550 reduction 276, 324, 328 frequency averaging 246 Oval window 457 Fresnel zone 564 Overlap processing 103 Fresnel zone size 564 Owl 505 ground effect 540 Owl wing 479 ground plus diffraction combined 556 Panel method solver 164 ground plus double diffraction Perception threshold 16 561 Period 61

k k

Index 601

Periodic amplitude variation 329 Quadrupole 121, 127 Periodic infrasound pulse 364 Phase control 483 Radiosonde 399 Phon 63 Radius of curvature 193 Pink noise 81, 306 refracted wave 194 Pistonphone 296 Random amplitude variation 329, 453 Pitch Random noise angle 161 pink 81 control 2, 481 white 81 RANS modelling 163, 169 Pitch-regulated wind turbines 147, 148 Ray path lengths 529, 530 Plane-wave reflection coefficient 520 Ray travel time 529, 530 Planetary gear 150 Rectangular window 98 Point-spread function 419 Reflected-ray path length 531 Poisson window 101 Reflected-ray propagation time 531 Power spectral density 92 Reflection coefficient 516, 521 scaling factor 99 incoherent 524 Power spectrum 90 plane-wave 520 RMS value 102 spherical-wave 521 scaling factor 99 Regression analysis 310, 313, 501 Power spectrum (see auto power spectrum) outliers 311, 314 Precautionary principle 453 Regulations 32, 38 Predicted sound pressure level 211 improvements 499 k Primary wind screen 306 k statistical analysis 501 Propagation modelling Reissner’s membrane 457 infrasound 210 Retarded time 124 low-frequency noise 210 Reynolds averaged Navier–Stokes equations offshore wind farm 272 169 procedure 210 Reynolds number 120 source-height effects 209 RMS 58 Propagation models Rods of Corti 459 CONCAWE 214 Room acoustic resonances 76 Danish EPA 212 Room modes Danish low-frequency 213 number 78 Harmonoise 261, 573 Room reverberation time 79 ISO9613-2 224 Root mean square 58 NMPB-2008 231, 505 Roughness length 191, 192 Nord2000 243 Round window 457 simple models 212 Rumbling 445 Swedish 212 uncertainty 211 Sample rate 296 Propeller anemometer 397 Sampling frequency 82, 103 Pseudo-noise 300 Scaled spectrum 98 Psycho-acoustic annoyance 351 Seasickness 450 Psycho-acoustic descriptors Secondary wind screen 304, 305 fluctuation strength 349 Segmented terrain profiles 539 noise 349 Semi-empirical noise prediction models Pulsating 450 160

k k

602 Index

Separated wake 138 travel time 206 Separation 130 variables 204 point 121 Source location Separation-stall noise 139 beamforming 386 Serrated trailing edge 480 Specific heat ratio 519 Shear exponent 18 Spectral density 90 Simple harmonic motion 81 Spectral leakage 98 Sinc function 320 Spectrogram 336 Skewness 60 Spectrum analysis (see frequency analysis) Sleep disturbance 437 Speed of sound 61, 63, 196 Slow response 295 gradient 194 SODAR 397 Spherical source 63 Solar panels 298 Spherical spreading 183 Sones 350 Spherical-wave reflection coefficient 516, Sonogram 363 521 Sound Stall 120, 477, 481 in rooms 76 control 3 intensity 63, 64 flutter 148 level meter 295 induced vibrations 148 quality 351 regulated wind turbines 148 speed gradient 188 Standard deviation 59, 393 transmission 276 Standards 29 k Sound power 63 AS4959 (2010) 31 k apparent sound power level 174 IEC 61400-11 (2012) 29 computational methods 168 ISO 1996 29 measured data analysis 172 ISO1996-1971 30, 33 measurement 169, 171 ISO9613-2 24, 28 measurement instrumentation NZS6808 (2010) 31 170 Standing waves 76, 77, 322 measurement uncertainty analysis Stapes 456 173 Statistical descriptors 59 prediction of total 168 Statistical sound levels 75 turbulent inflow noise 166 Statutory nuisances 32 wind speed analysis 173 Steering location 417 Sound power estimation Steering vector 417 computational techniques 158 Streamlines 129 prediction 157 Strouhal number 133 semi-empirical models 158, 161 Structural resonances 327 simple models 158 Subtraction of decibels 70 Sound pressure 63 Surface roughness 191 peak 58 Surface wave 524 units 62 Symptoms 437, 452 Sound ray Synchronous averaging 105 arc length 204 Synchronous sampling 105 curvature 193, 194, 526 maximum height 198, 199, 530 Tectorial membrane 459 radius of curvature 199, 526, 530 Temperature inversion 189

k k

Index 603

Temperature measurement 399 Triangular window 100 Thickness noise 147 Tuned mass dampers 486 Threshold of hearing (see hearing threshold) Tunnel of Corti 459 Thrust coefficient 159 Turbine blades Thumping noise 140, 144, 169, 445, 450, aero-elastic response 148 453, 481 Turbine inflow noise model Time domain high-frequency 167 sample rate 82 low-frequency 167 Timestamp 289 Turbine sound power Tip apparent sound power level 174 loss effects 162 blunt trailing-edge noise 166 loss factor 162 Class I models 158 noise 140 Class II models 158 vortex 121, 130 Class III models 158 vortex noise computational techniques 158, 168 semi-empirical model 165 measurement 169–173, 175 Tollmein–Schlicting waves 134 prediction 157, 168 Tonality semi-empirical methods 158, 159 audibility 353, 356 simple models 158 classifying spectral lines 355 turbulent inflow noise 166 IEC61400 assessment 353 wind speed analysis 173 masking level 353, 356 Turbulence 119, 122 k measurements 361 energy cascade 122 k penalty 352 interaction noise 141, 144 tone level 356 leading-edge interaction noise 141 Tonality assessment 352, 362 sound production 122, 124 DIN45681 356 spectraofwind 300 IEC61400 354 Turbulent ISO1996-2 358 flow 122 ISO1996-2 simplified 360 inflow noise 160, 166 Joint Nordic method 352 length scale 142 Trailing edge pressure fluctuations 300 bevelling 141 sound production 119, 122 serrations 141 trailing-edge noise 137 vortex shedding 136 Tympanic membrane 455 Trailing-edge noise 130, 131, 164 blunt, tonal 136, 138 Ultrasonic anemometer 396, 397 directivity 131 Uncertainty (see Measurement uncertainty) feedback loop 134 272 low-frequency peak 133 analysis 173 reduction 479, 505 analysis, beamforming 421 separation 138, 139 measurement 387 sound power level 164 Uncertainty principle 105 tip 139, 141 Uninterruptible power supply 299 tonal 134, 136 Unsteady turbulent 131, 134 blade loading 143 Transition 120 drag 147

k k

604 Index

Unsteady (contd.) coefficient 190 lift 141, 147 noise 144, 145 thickness noise 147 Wind speed flow separation 147 atmospheric stability effects 403 Upwind propagation 524 hub height 309 URANS modelling 169 logarithmic profile 401, 403 measurement 395 Vacil 349 power curve 400 Variance 59 Wind tunnel 408 Vegetation screening 221 acoustic measurements 413 Vertical sound-speed gradient 194 anechoic 413 Vertical sound-speed profile beamforming 415 equivalent linear 527 contraction 410 Vertical temperature profile 194 diffuser 413 Vibration 467 free-jet, anechoic 414 absorbers 486 microphone array 415 detection 282 open-jet type 411 generation 281 open-return type 409 instrumentation 394 screens 409 measurement 393 shear layer correction 415 propagation 280, 281 source location 415 threshold 282 vibration isolation 413 k Vibroacoustic noise 146 working section 410 k Viscous shear 129 Wind tunnel testing Vortex 121 beamforming 422 formation noise 140 scaled rotor 422 shedding 137 Wind turbine wake model 163 Aeolus II 6 AWEC-60 6 Wake deficit 16 Balaklava 3 Wavelength 60 Darrieus 5 Weighting networks 73 Gamma 60 6 Welch window 102 Gedser Mill 4 White noise 81, 306 generated energy 8 WHO guidelines 25 Growian 6 Whoomping noise 453 Hütter-Allgaier 4 Wind farm layout 487 history 2,4,5,7,13 Wind farm noise horizontal-axis 2 annoyance assessment 277 installed power 8 consensus 52 LS-1 7 Wind measurement 395 MOD-0 7 Wind screen 301, 302 MOD-0A 7 insertion loss 306 MOD-1 7 multilayer 304 MOD-2 7 performance 303 MOD-5B 8 secondary 304 NEWECS-45 6 Wind shear 15, 18, 188, 481 Neyrpic 4

k k

Index 605

Nibe A 6 Wind vane 396 Nibe B 6 Wind-induced noise 300 Tvind 6 reduction 305 vertical-axis 2, 5 WTS-3 7 Yaw control 3 WTS-4 8 WTS-75 7 Z-weighting 72 Wind turbine syndrome 440 Zero padding 105

k k

k