Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
권호 표지
DOI QR코드

DOI QR Code

Numerical Analysis on the Low Noise Designs of Savonius Wind Turbines by Inducing Phase Difference in Vortex Shedding

와류이탈 위상차를 이용한 사보니우스형 풍력터빈의 소음 저감 설계에 관한 수치적 연구

  • Received : 2013.08.01
  • Accepted : 2013.12.17
  • Published : 2014.03.01
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, low noise designs for a Savonius wind turbine were numerically investigated. As was reported in our previous study, the harmonic components with a fundamental frequency higher than the BPF were identified as being dominant in the noise spectrum of a Savonius wind turbine, and these components were a result of vortex shedding. On a basis of this observation, an S-shaped blade tip is proposed as a means of reducing the noise generated by small vertical(Savonius) wind turbines. This blade induces phase differences in the shedding vortices from the blades, and thus reduces the noise from the wind turbine. The aerodynamic noise characteristics of the conventional and "S-shaped" Savonius turbines were investigated by using the Hybrid CAA method where the flow field around the turbine is computed using the CFD techniques and the radiated noise are predicted by applying acoustic analogy to the computed flow field data. The degree of noise reduction resulting from the proposed design and its reduction mechanism were confirmed by comparing the predicted noise spectrum of these turbines and the flow characteristics around them.

본 논문에서는 사보니우스형 풍력터빈의 저소음 설계에 관한 연구를 수행하였다. 선행연구를 통해 BPF 보다 높은 주파수를 기본주파수로 가지며 발생하는 하모닉 성분의 순음소음이 사보니우스형 풍력터빈의 주요한 소음임을 밝혔고, 이러한 하모닉 성분의 소음은 와류에 의한 것임을 확인하였다. 본 연구에서는 이러한 선행연구결과를 바탕으로, 사보니우스형 풍력터빈의 저소음 설계를 위해 이탈되는 와류에 위상차를 유도할 수 있는 터빈 날개 끝단을 도입하였다. CFD 기법 및 음향상사법을 적용한 복합 전산공력음향학 기법을 적용하여 제안한 저소음 사보니우스형 풍력터빈의 방사 소음을 수치적으로 예측하였고, 기존의 형상과 비교를 통해 소음 저감 효과를 확인하였다.

Keywords

References

  1. Kim, S., 2013, "Investigation on the Flow Noise Characteristics of Savonius-Type Vertical-Axis Wind Turbines," Master Thesis, Pusan National University.
  2. Kim, S. and Cheong, C., 2013, "Numerical Analysis on the Flow Noise Characteristics of Savonius wind Turbines," Transaction of the KSNVE, Vol. 23, No. 6. pp. 496-501. https://doi.org/10.5050/KSNVE.2013.23.6.502
  3. Savonius, S. J., 1931, "The S-Rotor and its Applications," Mech. Eng., Vol. 53, pp. 333-338.
  4. Fluent 12.0 Theory guide, ANSYS (2009).
  5. Lighthill, M. J., 1952, "On Sound Generated Aerodynamically. I. General theory," Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences, Vol. 211, pp. 564-587.
  6. Lighthill, M. J., 1954, "On Sound Generated Aerodynamically. II. Turbulence as a Source of Sound," Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences, Vol. 222, pp. 1-32.
  7. Curle, N., 1955, "The Influence of Solid Boundaries Upon Aerodynamic Sound," Proceedings of the Royal Society of London, Vol. 231, pp. 505-514.
  8. Ffowcs Williams, J. E. and Hawkings, D. L., 1969, "Sound Generation by Turbulence and Surfaces in Arbitrary Motion," Philosophical Transactions of the Royal Society, Vol. 264, pp. 321-342. https://doi.org/10.1098/rsta.1969.0031
  9. Blackwell, B. F., Sheldahl, R. E., Feltz, L. V., 1977, "Wind Tunnel Performance Data for Two-and Three-Bucket Savonius Rotors," Journal of Energy, Vol. 2, pp. 160-164.
  10. Heo, S., Kim, D., Cheong, C. and Kim, T.-H., 2011, "Prediction of Internal Broadband Noise of a Centrifugal Fan Using Stochastic Turbulent Synthetic Model," Transactions of the Korean Society for Noise and Vibration Engineering, Vol. 21, No.12, pp. 1138-1145. https://doi.org/10.5050/KSNVE.2011.21.12.1138
  11. Howe, M. S., 1991, "Aerodynamic Noise of a Serrated Trailing Edge," Journal of Fluids and Structures, Vol. 5, pp.33-45. https://doi.org/10.1016/0889-9746(91)80010-B
  12. Moreau, D. J., Brooks, L. A. and Doolan, C. J., 2012, "On the Noise Reduction Mechanism of a Flat Plate Serrated Trailing Edge at Low-to-Moderate Reynolds Number," 33rd AIAA Aeroacoustics Conference.