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300W급 Savonius 형 수직축 풍력발전기의 유동소음특성에 관한 수치적 연구
김상현(Sanghyoen Kim),이광세(Gwangse Lee),정철웅(Cheolung Cheong) 한국소음진동공학회 2012 한국소음진동공학회 학술대회논문집 Vol.2012 No.10
In this paper, flow noise characteristics of Savonius-type vertical-axis wind turbines are numerically investigated using hybrid CAA techniques. High frequency harmonics as well as BPF components are identified in the predicted noise spectra from a Savonius wind turbine. As the BPF components belong to infrasound, the higher harmonic components affects human response dominantly. Further analysis is performed to investigate the reason causing the higher frequency harmonic noise by changing operational conditions of a Savonius wind turbine. Based on this result, it is revealed that the frequency of higher harmonic components is determined by the radius of blades and angular velocity of Savonius wind turbine.
Clark-Y 수중익형 캐비테이션 유동 소음 특성 분석
구가람(Garam Ku),김상현(Sanghyoen Kim),정철웅(Cheolung Cheong),하콩투(Cong Tu Ha),박원규(Warn-Gyu Park) 한국소음진동공학회 2016 한국소음진동공학회 학술대회논문집 Vol.2016 No.4
In this study, computational fluid dynamics techniques are applied to simulate cavitation flow and the noise caused by cavitation is predicted by applying the acoustic analogy to the predicted flow. The predicted results of cavitation flows are compared with the measurement and other prediction obtained from references available in terms of surface pressure distribution and the variation of periodic cavitation pattern. There are good agreements between these results. The noise sources are modeled as monopole and dipole sources. Then, the predicted noise results are analyzed in terms of directivity and SPL spectrum. Since the lift of the hydrofoil is higher than the drag, dipole source is dominant in the direction normal to the mean flow while monopole source is dominant in the direction parallel to the mean flow.