• Title/Summary/Keyword: acoustic ray theory

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Prediction of Wind Farm Noise with Atmospheric Stability (대기 안정 상태에 따른 풍력 단지 소음 전파 예측)

  • Son, Eunkuk;Lee, Seunghoon;Jeon, Minu;Lee, Soogab
    • 한국신재생에너지학회:학술대회논문집
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    • pp.42.2-42.2
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    • 2011
  • Noise generated from wind turbines has been predicted by numerical methods. Sound pressure level(SPL) on the turbines is predicted after aerodynamic analysis is carried out by Wind Turbine Flow, Aeroacoustics and Structure analysis (WINFAS) code. The level of each panel of acoustic sphere is determined by the sum of tonal, turbulence ingestion and airfoil self noise. With the noise source database, the acoustic sphere, SPL on the ground is calculated using the model based on acoustic ray theory. The model has been designed to consider the effects on the condition of terrain and atmosphere. The variations of SPL on the ground occur not only because of the different source level but also because of the nonuniform distributions of the sound speed along the height. Hence, the profile of an effective sound speed which is the sum of the contribution of sound speed to a temperature gradient and a wind speed variation is used by the theory based on atmospheric stability. With the integrated numerical method, the prediction of sound propagation on the wind farm is carried out with the states of the atmospheric stability.

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A precision analysis of Baengnyeongdo Multi-beam echosounder data using acoustic ray theory (음선이론을 이용한 백령도 부근해역 다중빔 수심측량 자료의 수직.수평 오차 분석)

  • You, Seung-Ki;Joo, Jong-Min;Choi, Jee-Woong;Kim, Young-Bae;Jung, Hyun;Kim, Seo-Cheol;Park, Sung-Kyeu
    • 한국지구물리탐사학회:학술대회논문집
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    • pp.167-173
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    • 2009
  • Bathymetry survey around the Baengnyeong-do was made by the Korea Hydrographic and Oceanographic Administration (KHOA), using the Simrad EM3000 Multi-Beam EchoSounder (MBES) mounted at the hull of the R/V Badaro 1. Sound velocity were monitored with frequent sound velocity profiler(SVP) casts during the acoustic measurements. The depth distribution and fluctuation of thermocline varied locally owing to the effect of several current flows such as Kuroshio current and Yellow sea coastal waters. These uncertainties cause the falling-off in accuracy of MBES results. In this paper, the bathymetry results will be presented and their accuracy will be discussed along with comparisons to the time and spatial variations in sound velocity profile.

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