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Time Domain Prediction and Analysis of Low Frequency Noise from Wind Turbine using Hybrid Computational Aeroacoustics (CAA) Method

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(1)

⊳㬧#ⷂ♮#ኳᷣⴊ㭣㬗+FDD,#⇧≓ⴂ#ⴲⱧ㬚#

⢚ᇂ⮿⮫#㩋ᷣ㛮␆#ⶾ⺺㣊⟖#❊ⴊ#⯆㏟ኺ#⍂⛛

‹‡‘ƒ‹”‡†‹…–‹‘ƒ†ƒŽ›•‹•‘ˆ‘™ ”‡“—‡…›‘‹•‡ˆ”‘

‹†—”„‹‡—•‹‰ ›„”‹†‘’—–ƒ–‹‘ƒŽ‡”‘ƒ…‘—•–‹…•ȋȌ‡–Š‘†

ҙԓʂॡİşćėॡҙ  ইʂܼėغ

ۿսێۙțښێս܁ێۙțښێ޽࢘ێۙțښێ

ొ ߧ: LowsonۆڼॳԜԐ֩ںۋڌॠي֨ÂًٖقԴॄͳࢢҾۆ۹ܳࣷսՙڼںٚࠑॠٕČ, ěʹՙڼڙ˞ۆ

şيʪεқԵॠٕɰ. ՙڼڙڷͿԴǨÒ-ŧԜथŒؓͳқपεĵॠşڦॠيXFOILεۋڌॠٕɰ. ۋ˺, ՙڼ

ٚࠑ֨ۓͳÉۍڮॢڅՙԜۆ৪ںćԓॠşڦ३ǨÒ-ŧںي͠ÒۆڅՙͿқॣॠٕɰ. ՙڼڙں৪Ծʴ२, À՚ʪ२, ՚ʪ२ڷͿқνॠيܳࣷսşيʪεқԵॠٕɰ. ǚڷͿ, ٚࠑ֟घ࣡ͤںڏڌܼۍॄͳࢢҾقʂॠي

ࠑ܁ॢ۹ܳࣷսՙڼęҼİॠٕČ, ŔĀęॄ՚ݒÀق˰͆৪ԾʴՁқۋ۹ܳࣷսقԴࡾóşيॠəìںঝۍ ॠٕɰ.

ෑਕ૳ઘ: ॄͳࢢҾ, ۹ܳࣷՙڼ, Lowson ڼॳԜԐ֩, ҄०CAA ѓѪ

ABSTRACT: Using Lowson’s acoustic analogy, low frequency noise of a wind turbine (WT) is predicted in time domain and the noise sources contributing to the low frequency noise is analyzed. To compute averaged pressure distribution on blades of the WT as noise source, XFOIL is utilized. The blade source domain is divided into several segments along the span direction to compute force exerted on air surrounding the blade segments, which is used as input for noise prediction. The noise sources are decomposed into three terms of force fluctuation, acceleration and velocity terms and are analyzed to investigate each spectral contribution. Finally, predicted spectra are compared with measured low frequency noise spectrum of a wind turbine in operation. It is found that the force fluctuation component contributes strongly in low frequency range with increasing wind speed.

Keywords: W ind turbine, Low frequency noise, Lowson's acoustic analogy, Hybrid CAA method PACS numbers: 43.28. Ra

School of Mechanical Engineering, Pusan National University, Busan 609-745, Republic of Korea

(Tel: 82-51-510-3205, Fax: 82-51-514-7640)

*Դ΁

ʂ঍սथ߹ॄͳࢢҾڹϔڍ۹՚ڷͿধۻॠČ

ŔǨÒ-ŧ(blade)ۋ҃ࣀ3Òۋॠےق˰͆ǨÒ-ŧ

ࣀęܳࣷսܓজՙڼ(BPF ܓজՙڼ)ڹ۹ܳࣷս (low frequency) / ߣ۹ܳࣷս(infrasound) ًٖقࡾó

şيॢɰ. ߯ŖॄͳࢢҾ۹ܳࣷս/ߣ۹ܳࣷսՙ ڼěʹथÀşѪ, ࣢Ձфٖॳقʂॢٍĵ˞ۋս

ॱʼČەڷ϶, ۋəॳ঳ĶÀѻॄͳࢢҾۍݒ̚

əथÀ֨۹ܳࣷս/ߣ۹ܳࣷսՙڼथÀÀप॥

̚əÌজʾսەڼںؒ֨ॢɰ. [1-3]

Ffowcs Williams ٮHawkings ֩ڹڮʴǴړݔۋə

ڼڙقʂॢێъۺۍڼۤٚࠑ֩ۋɰ. ۋεۋڌॢ

ধۻۙ(rotor) ̚əअ(fan)ۆѓԐՙڼٚࠑۆąڍ,

ܳرݕǨÒ-ŧԜؓͳқपεŔʂͿڼڙڷͿۺڌ ॠيՙڼںٚࠑॣսەɰ. [4] Lighthill [5] ۆڼॳԜԐ

֩ںц࢖ڷͿLowson [6] ڹধۻॠəڼڙقۺڌ

ॠşقठνॢ঍ࢗۆڼۤٚࠑ֩ںڮʪॠٕɰ.

(2)

Ilj1#41#Vfkhpdwlf#ghvfulswlrq#ri#zlqg#wxuelqh#qrlvh#suhglfwlrq#surjudp1

Lowson ۆٚࠑ֩ڹڼڙںࡾó৪ۆԾʴ२, ՚ʪ२

ŔνČÀ՚२ڷͿĵқॢɰ. ۋ˺, ৪Ծʴ२ęÀ

՚ʪ२ڹڙڼۤ(far field)قşيॠČ, ՚ʪ२ڹŖ ڼۤ(near field)ںʂशॠəBPF ܓজՙڼڙ˞ۋɰ.

঳Ϊ(wake)ٮǨÒ-ŧÂԜ঒ۚڌقۆॢٖॳں

И֨ॣսەڷ϶ধۻ߹ѓॳڮʴۋێ܁ॠɰϸ, ێъۺڷͿَοėÂقԴধۻۙ̚əअڹধۻق

˰δǨÒ-ŧܳڦۆڮʴঞą(ڮ՚фыڼÁ)ۋČ

܁ۺۋ͆ČÀ܁ॣսەɰ. ъϸ, ॄͳࢢҾڹČʪ

ѻॄ՚қपق˰͆ধۻÁʪѻǨÒ-ŧڮʴঞą ۋѺॢɰ. Ŕ͠дͿॄͳࢢҾۆǨÒ-ŧܳڦۆथ Œজʽڮʴۤں३Եॠʌ͆ʪ, ŔǨÒ-ŧԜؓͳ

ۤۋ֨Âق˰͆Ѻॢɰ. ݌, ॄͳࢢҾBPF ܓজՙ ڼقʂॢ৪Ծʴ२ۆşيʪεşʂॣսەɰ.

ٍ҆ĵقԴ, ॄͳࢢҾۆ۹ܳࣷսٚࠑںڦॠي

҄०ۻԓėͳڼॳॡѓѪ(҄०CAA ѓѪ)ںۋڌ

ॢɰ. ۋѓѪڹڮʴۤقʂॢڼؓۆٖॳۋۚɰə

À܁ॠقڼڙۋʼəڮʴۤںڍԸćԓॠČڼڙ ںϿʝτॢ঳ڼۤۆćԓںսॱॠəѓѪۋɰ. [7]

҄०CAA ѓѪǴڼۤćԓڹLowson ڼॳԜԐ

֩(Lowson’s acoustic analogy), ܵ-֬ॹۙÀġʂً

ՙڼϿʝ [8] ęܵ-֬ॹڮۓġʂًՙڼϿʝ [9] ˞ں

ࣀ३սॱॢɰ. ܵ-֬ॹۙÀġʂًՙڼϿʝęܵ-

֬ॹڮۓġʂًՙڼϿʝڹşܕۆٍĵ˞قԴ

ॄͳࢢҾՙڼںٚࠑॠşڦ३ۺڌʼرٵڷ϶,

҆ȦЛǴقԸɳݓ۹ܳࣷսًٖقԴ܁͟ۺۍ

ٚࠑĀęҼİεڦ३ČͲॢɰ. [10] ݌, Lowsonۆڼ ॳԜԐ֩ںۋڌॢBPF ܓজՙڼڙقʂڿॠə۹

ܳࣷսࢢҾՙڼقʂॢ֨ÂًٖقԴۆٚࠑф

қԵۋٍ҆ĵۆܳڅЀۺۋɰ.

Lowson ڼॳԜԐ֩, ܵ-֬ॹۙÀ/ڮۓġʂًՙ ڼϿʝڹॠǣۆGUI(Graphic User Interface) ॒ͿŔ

͖ڷͿ܃ۚॠٕڷ϶, Áڼؓٚࠑ֨ۓͳÉćԓ ںڦ३XFOIL [11] ںۋڌॠيėͳ३Եںॢɰ. ۋ

˺, MPI(Message Passing Interface)εۋڌॠيѿ͵ć ԓںॢɰ. Ò͜ۺۍࢢҾՙڼٚࠑ॒ͿŔ͖ĵՁ ʪəFig. 1ęÏɰ. GUI ॒ͿŔ͖ڹߪ4ÒۆϿ˗Ϳ

ĵՁʼؽɰ. C# ںۋڌॠيGUI ঞąę঳ߌνę

܁ںĵইॠٕڷ϶, Fortranεц࢖ڷͿXFOILںѿ

͵३Եॢɰ.

ÁĵՁϿ˗ۆşɠںۋ३॥ڷͿԴ, ՙڼٚࠑ ۆێʹۆę܁ںԺϼॣսەɰ.

ڍԸࢢҾՙڼٚࠑ֨ÁϿ˗ܼǨÒ-ŧ܁҃

(blade data) Ͽ˗ͿҙࢢǨÒ-ŧۆĵՁقرपێ, Ҽ

ࣥρÁ(twist angle), ţۋ(chord)ۆধۻۙъąѓॳ

қपٮۤ޳Á(pitch angle), ۤ޳߹(pitch axis) фҼࣥ

ρ߹(twist axis)ˣںԺ܁ॢɰ.

ɰڼڷͿ, ࢢҾĵʴܓæ(operating condition) Ͽ˗

قԴČʪѻॄ՚қपٮধۻ՚ʪ, ʂş٣ʪٮԜ

ʂ֥ʪˣںۓͳॢɰ.

(3)

Wdeoh#41#Jurxqg#urxjkqhvv1

^43`

Terrain Description z

0

(mm) Very smooth, ice or mud 0.01

Calm open sea 0.2

Blown sea 0.5

Snow surface 3

Lawn grass 8

Rough pasture 10

Fallow field 30

Crops 50

Few trees 100

Many trees, hedges 250 Forest and woodlands 500

Suburbs 1500

Centers of cities with tall buildings 3000

ǨÒ-ŧ܁҃ٮࢢҾĵʴܓæںԺ܁ॢ঳ėͳ ३Ե(aerodynamic analysis) Ͽ˗قԴ, XFOILڹۙÀ

ġʂًՙڼٚࠑࡑ˚(BPM code)ۆۓͳÉۍąć

ࠗѺڦ˃ƍ(boundary layer displacement thickness)ٮ

Lowson ۆڼॳԜԐ֩ۆۓͳÉۍǨÒ-ŧԜؓͳ ćս(pressure coefficient)εćԓॢɰ. ۋ˺, BEM ۋ

΁(blade element momentum theory) [12] ق˰͆ǨÒ-ŧ ںي͠څՙεқॣॠČধۻÁʪѻÁڅՙܳڦ

ڮʴܓæںʚۋࢢѮۋ֟জॢɰ. ŔνČڮʴܓæ

ʚۋࢢѮۋ֟εۓͳÉڷͿॠيÁڅՙقʂॢ

ėͳ३ԵڹXFOILںࣀ३սॱॢɰ.

ŔνČʂşܼǦΪÌʪ(turbulent intensity)ٮǦ Ϊࡾş(turbulent length scale)əݓशϸäࠜşÀ܁

ق˰͆ĵ३ݓČLowsonۆڮۓġʂًՙڼٚࠑ

֩(Lowson’s formula)ۆۓͳÉۋʽɰ. [10]

ধۻÁʪфǨÒ-ŧڅՙѻąćࠗѺڦ˃ƍ, ؓ ͳćս, ǦΪÌʪфࡾşəʚۋࢢѮۋ֟জʼر

ՙڼٚࠑ(noise prediction) Ͽ˗قۓͳʽɰ. ॄͳࢢ Ҿقěʹॢ˃ġʂًՙڼٚࠑϿʝۆۙՃॢۺ ڌфěʹս֩ڹZhuۆȦЛڷͿҙࢢ޷Čॣս

ەڷ϶, 2.2ٮ2.3 ۼقěʹ֩ںÒ͜ۺڷͿԺϼॠ

ٕɰ. [10]

҆ȦЛقԴəࢢҾ۹ܳࣷսՙڼۆܳʽқԵڹ

Lowson ڼॳԜԐ֩ںۋڌॢɰ. ۋ˺ڼڙںԾʴ २, ՚ʪ२ęÀ՚ʪ२ڷͿқνॠČ, Áܳࣷսş يʪεқԵॢɰ. ǚڷͿ, ٚࠑĀęٮࠑ܁Āęε

Ҽİॠي܁͟ۺڷͿॄͳࢢҾ۹ܳࣷսՙڼںқ Եॢɰ. ܁͟ۺҼİ֨ٚࠑĀęəܵ-֬ॹۙÀġ ʂًՙڼٚࠑϿʝ [8] ęܵ-֬ॹڮۓġʂًՙڼ

ٚࠑϿʝ [9] ںप॥ॢɰ.

**ՙڼٚࠑ֩

ճܑ࣢ණুंඑࡦ܄ࠫ

ǨÒ-ŧܳڦۆڮʴঞąںĀ܁ॠşڦॠيॄ

ͳࢢҾڷͿۓԐʼəČʪѻॄ՚ںϿʝτॠٕɰ.

Table 1 قIEC61400-11 [13] قۺڌॣսەəɰتॢ

ݓ঍ܓæق˰δݓशϸäࠜşÉں܁νॠيǣࢍ

Ǵؽɰ. ۋÉęIEC 61400-11 قԴ܁ۆॠČەəČ ʪѻॄ՚ěʹ֩ںۋڌॠيǨÒ-ŧڅՙѻۓԐ

ॄ՚ںćԓॢɰ. ३ɾ֩ڹɰڼęÏɰ.

.

(1)

يşԴ, z 0ref ə޷ܓݓशϸäࠜşÉڷͿ50 mm ۋ ɰ. z 0 əԺ࠘ʽॄͳࢢҾܳѺںÀۤڮԐॠóГ ԐॠəݓशϸäࠜşÉقʂڿॠ϶, Table 1ں޷ܓ ॠي50 mmͿԺ܁ॠٕɰ. HəॄͳࢢҾধۻܼۙ

֮ȭۋεۆйॠČ, z ref ə޷ܓȭۋͿ10 mق३ɾ

ॢɰ. V s əशܵॄ՚(standardized wind speed)ںǣࢍ

Ǵ϶, V z əȭۋzقڦ࠘ॢॄ՚ćͿҙࢢĵॢॄ՚

ں̹ॢɰ. ٍ҆ĵقԸ, ֩(1)ںۋڌॠيܳرݕश

ܵॄ՚ڷͿҙࢢČʪz ق˰δॄ՚V z ۆқपεً

ڷͿĵॠٕɰ. ३Եۼ޲εČͲॠϸ, ֩(1)ڹࢢҾ

ĵʴܓæϿ˗قԴ֬ॱॢɰ.

ஜਓ෠ୀԧֈ۩લীଣુ౸ࡦ܄

Brooks ˣڹNACA0012 قرपێقʂॢѓʂॢ

֬ॹںࣀ३ՙڼфڮʴ࣢Ձںࠑ܁ॠٕɰ. [8] Ŕ˞

ڹ ֬ॹ Āę˞ں ۋڌॠي, Ffowcs Williamsٮ

Hall [14] ۋ܃֨ॢ˓ۻقԴۆڼؓԓ͈֩ںşܵڷ

Ϳࠑ܁ՙڼںڮʴ࣢ՁÉڷͿҙࢢ॥սজॠٕɰ.

(4)

ۙÀġʂًՙڼϿʝܼǦΪąćࠗ-˓ۻ(turbulent boundary layer-trailing edge, TBL-TE) ՙڼęчν-֬՚

(separation and stall, S-S) ՙڼںॄͳࢢҾܳڅՙڼ ڙڷͿČͲॢɰ. [15] ۋ˞ܳڅՙڼϿʝ˞قʂॢ

ܵ-֬ॹۙÀġʂًՙڼٚࠑ֩ڹɰڼęÏɰ. [8]

,

(2)

,

(3)

. (4)

֩(2)قԴ(4) Ǵ, SPL p ęSPL s əÁÁؓϸ(pressure side) ęҙؓϸ(suction side)قʂڿॠəTBL-TE ՙڼ

Ͽʝۋ϶, SPL S-S ڹS-S ՙڼϿʝقʂڿॢɰ. ÁϿ ʝق˰δٚࠑĀęə1/3 ٢ࢍҵї˚ͪѲۆڼؓ

ۋɰ. 쩃G s * ǨÒҙؓϸقԴۆąćࠗѺڦ˃ƍ, 쩃G p *

əؓϸقԴۆąćࠗѺڦ˃ƍ, Məυॠս, 쨣Lڹ

֟अۆţۋεǣࢍǶɰ. ŔνČrڹقرपێ˓ۻ

ܼ֮قԴսڼ۾Âäνۋ϶, Də3޲ڙԜսڼ۾

ڦ࠘ق˰δѓԐڼۆѓॳ॥ս(directivity function) ۋɰ. Á֩قԴͿŔ॥ս঍ࢗۆڍࠑߒ२ڹ

Ffowcs Williams ٮHallۆ˓ۻԓ͈֩ڷͿҙࢢڮʪ ʽìۋČ, ǣϢݓڍࠑ२˞ڹ֬ॹĀęٮԓ͈֩

Âۆܳࣷսѻ޲ۋε҃܁ॠşڦॢ֩˞ۋɰ. [8]

ٍ҆ĵقԸ, ėͳ३ԵϿ˗قԴÁǨÒ-ŧڅՙ قʂॠيXFOILͿҙࢢؓϸęҙؓϸۆąćࠗѺ ڦ˃ƍεćԓॠČ, ՙڼٚࠑϿ˗قԸ֩(2)قԴ (4) εۋڌॠيۙÀġʂًՙڼںٚࠑॢɰ.

ஜਓ෠କ଺ֈ۩લীଣુ౸ࡦ܄

Lowson ڹAmiet [16] ۆڮۓġʂًՙڼقʂॢٚ

ࠑϿʝںঝۤॠي, ʂşܼۆǦΪࡾşٮǦΪÌ ʪͿҙࢢڮۓġʂًՙڼںٚࠑॠəϿʝں܃֨

ॠٕɰ. ۋ˺, ǦΪࡾşٮǦΪÌʪəݓ঍ܓæÀ

܁ق˰δ֬ॹۺϿʝͿĵॢɰ. [10] Lowson ۋ܃؋ॢ

ܵ-֬ॹڮۓġʂًՙڼٚࠑϿʝڹɰڼęÏɰ.

, (5)

, (6)

, (7)

, (8)

يşԴ, 쩐 0 əʂşнʪ, LəǦΪࡾş, I əǦΪÌʪ, K = 쩏 f c/uəࣷս, cəقرपێࡑ˚, uəथŒॄ՚, r əսڼ۾ęۆäν, dəǨÒȃҼ, LFCə۹ܳࣷ

ս҃܁२, S əؓ߹Ձ֨ر॥ս, 쩁G 2 = 1 - M 2 ۋɰ.

SPL H INF ęSPL L INF əÁÁČܳࣷսٮ۹ܳࣷսقʂ

ॢڮۓġʂًՙڼۆ1/3 ٢ࢍҵї˚ͪѲۋɰ. ҆

ȦЛقԴə۹ܳࣷսقԴČܳࣷսͿߎۋĵÂں

ČͲॢɰڼۆܵ-֬ॹڮۓġʂًՙڼٚࠑ֩ں

ۋڌॠٕɰ.

. (9)

֩(9)ۆۓͳÉۍǦΪࡾşٮǦΪÌʪəÁÁ

ɰڼ֩ڷͿҙࢢćԓॢɰ. [10]

, (10)

, (11)

يşԴ,

. (12)

ۋ϶, Z əݓϸڷͿҙࢢȭۋ, z 0 əTable 1ęÏۋГ

Ԑʽݓशϸäࠜşۋɰ. ۋͿԴ, ՙڼٚࠑϿ˗ق

(5)

Ը֩(5)قԴ(12)ںۋڌॠيڮۓġʂًՙڼںٚ

ࠑॢɰ.

-PXTPOଣේঃॷਐ

Lowson ۆڼॳԜԐ֩ڹێ܁ॢ՚ʪͿѿݕڏʴ ॠəڼڙقʂॢɰڼۆڼۤݓѕ֩ڷͿҙࢢڮʪ

ॣսەɰ. [6]

. (13)

ۋ˺, x i , y i (i=1,2,3) ڹÁÁսڼ۾ęڼڙقʂॢ

ܟशćεۆйॠ϶, M r ڹѯࢢrѓॳۆڼڙ՚ʪՁ қقʂॢυॠս, ѯࢢrڹڼڙقԴսڼ۾ڷͿॳ ॠəѯࢢ, rڹѯࢢrۆࡾş, a 0 əڼ՚, F i ə۾-৪ (point force) ں ǣࢍǴČ ‘[ ]’ڹ ݓٍ֨Â(retarded time) قԴÉںǣࢍǶɰ. ֩(13)ڹČ܁ʽ՚ʪͿѿ ݕڏʴںॠə۾-৪ۋ֨ÂقʂॠيԾʴॠݓ؍

ںąڍڼۋьԦॠݓ؍ڼںǣࢍǶɰ. ॠݓχ৪ ۋێ܁ॠʌ͆ʪধۻॠəąڍ, ধۻقԴԦşə

սڼ۾ʂҼÀ՚ʪۆٖॳڷͿՙڼۋьԦॢɰ.

ۋ͠ॢইԜڹێъۺۍধۻşćقԴьԦॠə

BPF ܓজՙڼۆڙۍۋ϶, ěʹՙڼںGutin ՙڼ ۋ͆Čʪॢɰ. [17]

ǨÒ-ŧԜŔνČܳڦǦΪڮʴۤۆқपՙڼ ڙ(distributed acoustic source)قۆॢڼۤڹɰڼ֩

ڷͿҙࢢćԓॣսەɰ.

. (14)

يşԴ, gəےۆۆڼڙڷͿԴԐŕۙ(quadrupole),

ֻŕۙ(dipole), ɳŕۙ(monopole)ͿϿʝτॣսە ɰ. ۹υॠսقԴəֻŕۙՙڼڙۆşيʪÀࡾş

˺Лق֩(14)قԴg = -F i / x i Ϳशইॣսەɰ.

ֻŕۙՙڼڙۆړݔےں3 ޲ڙDirac 쩃 ॥սͿ܁

ۆॠϸ, ėÂقԴړݔۋəқप۾-৪˞قۆॢڼ

ۤڹɰڼęÏۋǣࢍǷսەɰ.

. (15)

Lowson ڹ֩(14)قԴݓٍ֨ÂںČͲॢ쩃॥սۆ

ėÂ/֨ÂйқںČͲॠي, ےۆͿړݔۋ϶Ծʴ ॠə৪قۆॢڙڼۤęŖڼۤقʂॢ֩ں؉͒

ٮÏۋ܃֨ॠٕɰ.

ڙڼۤ:

. (16)

Ŗڼۤ:

.

(17)

֩(16) ǴF i / tə৪Ծʴ२, M r / təÀ՚ʪ २, ֩(17)ڹ՚ʪ२ںʂशॢɰ. ۋ˺, ǨÒ-ŧԜ

M r , r, x i , y i əBEM ںۋڌॠيĵॢɰ. [12] ॄͳࢢҾۆ

BPF ܓজՙڼں֩(16)ę(17)ںۋڌॠيćԓॠ϶, ۓͳÉۍ۾-৪ڹXFOILͿҙࢢĵॢÁڅՙѻؓ

ͳқपͿҙࢢĵॢɰ. [6] ۋ˺, ǦΪߎۋəۙڮߎۋ (free transition) ܓæۋɰ. ॄ՚6 m/s şܵ, XFOIL ć ԓ֨ǨÒ-ŧࣴ(tip) Ԝͪۋȧ݋սٮυॠսəÁ Á2.8 × 10 6 ٮ0.23ۋɰ.

***ٚࠑĀę

܃֨ॢѓѪق˰͆ॄͳࢢҾۆ۹ܳࣷսՙڼٚ

ࠑںսॱॠٕɰ. ۹ܳࣷսՙڼۆŔܳࣷսѩڦ قʂॢÁĶÀÂ܁ۆəԜۋॠ϶, ҆ȦЛقԴə

Ŕѩڦε20-160 HzͿ܁ۆॠٕɰ. ٚࠑêݒںڦ

ॢՙڼࠑ܁֨ڦ࠘əIEC61400-11 2 nd ۆşܵڦ࠘

1(reference position 1) ۋɰ. [13] ʂ͜ۺۍࠑ܁ڦ࠘ə

ࢢҾڷͿҙࢢأ120 m ̆رݕॠΪڦ࠘ۋɰ. ٚࠑ

֨, ֬܃ڏڌܼۍॄͳࢢҾۆǨÒ-ŧԺć܁҃ф

ŔĵʴܓæںۓͳÉڷͿԐڌॠٕɰ.

(6)

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Figs. 2 ٮ3ڹशܵॄ՚6 m/sقԴBPF ܓজՙڼǴ

৪Ծʴ२, À՚ʪ२ę՚ʪ२ۆşيʪεÁÁ֨ ęܳࣷսًٖقԴқԵॢĀęεǣࢍǶɰ. Fig. 2 ۆ֨ÂًٖٚࠑĀęεࣀॠي৪Ծʴ२ۆۻߕ ڼؓقʂॢşيʪεঝۍॣսەɰ. ̚ॢ, ܳرݕ

ڦ࠘قԴڙڼۤ/Ŗڼۤٚࠑ֩ڷͿҙࢢĵॢÁ

ڼؓÂڦԜ޲Ϳۍॠيۻߕڼؓۆ߯ʂݕफۋ

Ŗۿڼڙɳʫşيێ˺҃ɰۚɰəìں؎սە ɰ. Fig. 3ۆܳࣷսًٖٚࠑĀęə৪Ծʴ२ۋČ

޲BPFقԴࢀşيʪεÀݓəìںǣࢍǶɰ. ٚ ࠑĀęقԴŖڼۤٚࠑ֩Ǵ՚ʪ२ۆşيʪÀ1 st BPF قԴÀۤࡾɰ. ŔνČ֨ÂًٖĀęقԴঝۍ

ॣսەؽʏսڼڦ࠘قԴÁڼڙ२ÂڦԜ޲ق

ۆॢÂԾڷͿۍॢٖॳڷͿ1 st BPF قԴۻߕڼؓ

ۋ՚ʪ२قʂڿॠəڼؓ҃ɰۚóǣ١əìں

؎սەɰ.

Figs. 4 ٮ5əÁÁशܵॄ՚ۋ6 m/s ŔνČ9 m/s ێ˺, ॄͳࢢҾࠑ܁ՙڼʂҼՃܛΪۆ҄०CAA ѓѪق˰δٚࠑĀę˞ÂҼİεǣࢍǶɰ. [18] ۋ

˞Āęəٍ҆ĵǴÁBPF ՙڼڙ२ۆܳࣷսş يʪқԵęٍćॠيۋ३ॢɰ. ÁҼİəIEC 61400-11 şܵڷͿՙڼںࠑ܁ॢĀę(Measurement),

֩(16)ę(17)ͿҙࢢٚࠑॢĀę(Lowson code), Brooks, Pope ٮMarcoliniۆܵ-֬ॹۙÀġʂًՙڼϿʝę

Lowson ۆܵ-֬ॹڮۓġʂًՙڼϿʝقۆॢٚ

ࠑÂ०(BPM-L code), ǣϢݓəϿ˜ٚࠑĀęۆ०

(Total) ںप॥ॢɰ. [18]

(7)

Fig. 4 قԴॄ՚ۋ6 m/sۍąڍ۹ܳࣷսًٖقԴ

ġʂًՙڼڼؓࡾşÀBPF ܓজՙڼՁқۆŔࡾ

ş҃ɰȭɰəìں؎սەɰ. Ŕ͠ǣFig. 5ٮÏۋ

ॄ՚ۋ9 m/sͿݒÀॠϸ, ۹ܳࣷս(80 Hz ۋॠ)ًٖ

قԴġʂًՙڼՁқ҃ɰBPF ՙڼۆşيʪÀȭ

؉ݕɰ. ۋə֨Â, ܳࣷսқԵقԴঝۍॣսەؽ ʏČ޲BPF ՙڼقࡾóşيॠə৪Ծʴ२ۆٖॳ

˺Лۋɰ. ̚ॢ, ܁͟ۺڷͿ֬ࠑĀęٮٚࠑĀę À۞ێ࠘ॠəìںঝۍॣսەɰ. ࣢০ܵ-ąॹ֩

ġʂًٚࠑϿʝق߸ÀۺڷͿ۹ܳࣷՙڼۆٚࠑ

Ͽʝںप॥॥ڷͿ׆, ॄ՚ݒÀق˰δ80 Hz ۋॠ قԴۆѓԐڼؓۆݒÀąॳں۞ъٖॠČەڼں

؎սەɰ.

*7Ā΁

Lowson ۆڼॳԜԐ֩ęXFOIL ࡑ˚εۋڌॢ҄

०CAA ѓѪڷͿҙࢢॄͳࢢҾۆܳڅ۹ܳࣷՙ ڼՁқۍBPF ܓজՙڼںٚࠑॠٕɰ. BPF ܓজՙ ڼںÁÁ৪Ծʴ२, À՚ʪ२ę՚ʪ२ڷͿқν ॠيŔܳࣷսşيʪεқԵॠٕɰ. ŔĀę, ՚ʪ २ęÀ՚ʪ२ۋ۹޲BPFقԴࡾóşيॠəъϸ

৪Ծʴ२ڹČ޲BPFقԴܳͿşي॥ںঝۍॠٕ

ɰ. 㑰՚ۋ6 m/sٮ9 m/s ێąڍقʂॢ, ѓԐՙڼࠑ

܁ęٚࠑĀęϿ˃80 Hz ۋॠقԴॄ՚Ѻজق˰

δлÇॢڼؓࡾşѺʴتԜںٕ҃ɰ. ۋśüॢ

ѺজəČ޲BPF قʂڿॠəLowson ֩Ǵ৪Ծʴ २˺ЛۍìڷͿঝۍॠٕɰ. ̚ॢ܁͟ۺۆйق Դ҄०CAA ѓѪقşߣॢBPF ܓজՙڼٚࠑڹġ ʂًՙڼڙχقۆॢٚࠑĀę҃ɰ۹ܳࣷսقԴ

ٚࠑĀę܁ঝՁںॳԜ֨࢈սەɰəìںঝۍॠ

ٕɰ.

ٍ҆ĵقԴ, Čʪѻॄ՚қपقěʹॢ৪Ծʴ २ۋ۹ܳࣷսًٖقԴࢀşيʪεÀݙںঝۍॠ

ٕɰ. ۋəॄͳࢢҾथÀۤՙٮԺ࠘ۤՙÂۆČ ʪѻॄ՚şڐşқपÀԜۋॣąڍ, ۹ܳࣷսٖ

ًقԴՙڼथÀĀęə֬܃Ժ࠘ݓًقԴۆॄͳ ࢢҾ۹ܳࣷսՙڼ࣢Ձںʂशॠş৪˞սەڼ ںؒ֨ॢɰ. ۋٮÏڹЛ܃ε३Āॠşڦ३҆ٚ

ࠑѓ֩ںڿڌॣսەںìڷͿşʂॢɰ.

ÇԐۆŘ

ٍ҆ĵə2011țʪݓ֩ą܃ҙۆۦڙڷͿॢĶ قȃݓşցथÀڙ(KETEP)ۆݓڙںы؉սॱॢ

ٍĵę܃ۓɦɰ(No. 20113020020010-11-1-000).

3FGFSFODFT

1. G. Leventhall, “Infrasound from wind turbine,” Canadian Acoustics, 34, 29-36 (2006).

2. S. S. Jung, W.-S. Cheung, C. Cheong and S.-H. Shin,

“Experimental identification of acoustic emission character- istics of large wind turbines with emphasis on infrasound and low-frequency noise” (in Korean), J. Korean Phys. Soc.

53, 1897-1905 (2008).

3. L. D. Knopper and C. A. Ollson, “Health effects and wind turbines: A review of the literature,” Environ. Health-Glob.

10, 78-87 (2011).

4. J. E. Williams and D. L. Hawkings, “Sound generated by turbulence and surfaces in arbitrary motion,” Philos. T. Roy.

Soc. A. A264, 321-342 (1969).

5. M. J. Lighthill, “Sound generated aerodynamically (Bakerian Lecture),” Proc. R. Soc. Lon. Ser.-A. 267, 47-182 (1961).

6. M. V. Lowson, “The sound field for singularities in motion,” P. Roy. Soc. Lond. A Mat. 286, 559-572 (1965).

7. B. A. Singer, D. P. Lockard, and G. M. Lilley, “Hybrid acoustic predictions,” Comput. Math. Appl. 46, 647-669 (2003).

8. T. F. Brooks, D. S. Pope, and M. A. Marcolini, “Airfoil self-noise and prediction,” NASA reference publication 1218, 1989.

9. M. V. Lowson, “A new prediction model for wind turbine noise,” Wind Eng. 18, 51-61 (1994).

10. Wei Jun Zhu, Modelling of Noise from Wind Turbine, (M. S.

thesis, Technical University of Denmark, 2004).

11. Drela, Mark, “XFOIL: An analysis and design system for low reynolds number airfoils,” in Low Reynolds Number Aerodynamics, edited by Thomas J. Mueller (Springer, Berlin Heidelberg, 1989), pp. 1-12.

12. Martin O. L. Hansen, Aerodynamics of Wind Turbines 2

nd

ed., (Earthscan, London, 2008), pp. 85-103.

13. IEC 61400-11:2002, Wind Turbines Part 11: Acoustic noise measurement techniques, 2002.

14. J. E. Williams and L. H. Hall, “Aerodynamic sound generation by turbulent flow in the vicinity of a scattering half plane,” J. Fluid Mech. 40, 657-670 (1970).

15. G-S Lee, C. Cheong, S-H. Shin, and S-S. Jung, “A case

study of localization and identification of noise sources

from a pitch and a stall regulated wind turbine,” Appl.

(8)

Acoust. 73, 817-827 (2012).

16. R. K. Amiet, “Acoustic radiation from an airfoil in a turbulent stream,” J. Sound Vib. 41, 407-420 (1975).

17. L. Gutin, “On the sound field of a rotating propeller,”

Translated as NACA Thec. Memo 1195 NACA, 1936.

18. G-S. Lee, C. Cheong, H-T. Kim, and W-H. Joo, “Prediction and analysis of wind turbine low frequency noise” (in Korean), J. Acoust. Soc. Kr. Suppl. 1(s) 32 , 250-254 (2013).

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