Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

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

DOI QR Code

Characteristics of Wall Pressure over Wall with Permeable Coating

침투성 코팅 처리된 벽면 주위의 벽 압력 특성

  • Received : 2010.05.13
  • Accepted : 2012.08.29
  • Published : 2012.11.01
Download PDF
⟨ Previous Next ⟩

Abstract

Fluctuating wall pressures were measured using an array of 16 piezoelectric transducers beneath a turbulent boundary layer. The coating used in this experiment was an open-cell, urethane-type foam with a porosity of approximately 50 ppi. The ultimate objective of the coating is to provide a mechanical filter to reduce the wall pressure fluctuations. The boundary layer on the flat plate was measured by using a hot wire probe, and the CPM method was used to determine the skin friction coefficient. The wall pressure autospectra and streamwise wavenumber-frequency spectra were compared to assess the attenuation of the wall pressure field by the coating. The coating is shown to attenuate the convective wall pressure energy. However, the relatively rough surface of the coating in this investigation resulted in a higher mean wall shear stress, thicker boundary layer, and higher low-frequency wall pressure spectral levels compared to a smooth wall.

16채널 어레이 마이크로폰을 이용하여 난류 유동장 내 벽면 압력섭동에 대한 측정을 수행하였다. 본 실험에 사용된 코팅재질은 약 50 ppi (pores per inch)의 다공성 구조로 이루어진 우레탄 물질로 이루어져 있다. 코팅의 주된 목적은 난류 유동장 내 최소한의 공간을 유지하면서 대류속도로 진행하는 난류 와들을 필터링하는 역할을 하는 것이다. 평판 위 경계층의 측정은 열선 유속계를 이용하였으며 표면 마찰계수 값을 얻기위해 CPM법을 사용하였다. 벽압력 스펙트럼과 파수-주파수 스펙트럼 측정은 코팅에 의해 얼마나 에너지가 저감되는 지를 비교하기 위해 사용되었다. 벽면 코팅은 대류하는 무차원 벽면섭동압력에너지를 저감시켰지만, 컴플라이언트 코팅된 벽면 거칠기로 인해 일반 강체 평판에 비해 상대적으로 발달된 경계층을 형성하였으며 벽면 평균전단응력과 저주파수 압력스펙트럼 레벨도 함께 증가하였다.

Keywords

References

  1. Wills, J. A. B., 1970, "Measurements of the Wave-Number/Phase Velocity Spectrum of Wall Pressure Beneath a Turbulent Boundary Layer," J. Fluid Mech., Vol. 45, Part 1, pp. 65-90.
  2. Blake, W. K. and Chase, D. M., 1971, "Wavenumber-Frequency Spectra of Turbulent Boundary Layer Pressure Measured by Microphone Arrays," J. Acoust. Soc. Am., Vol. 49, No. 3, Part 2, pp. 862-876. https://doi.org/10.1121/1.1912427
  3. Farabee, T. M. and Geib, F. E., 1991, "Measurements of Boundary Layer Pressure Fluctuations at Low Wavenumbers on Smooth and Rough Walls," Proceedings of the ASME Symposium on Flow Noise Modeling, Measurement, and Control, Noise Control and Acoustics, Vol. 11, pp. 55-68.
  4. Panton, R. L. and Robert, G., 1994, "The Wavenumber-Phase Velocity Representation for the Turbulent Wall-Pressure Spectrum," ASME J. of Fluid Eng., Vol. 116, pp. 477-483. https://doi.org/10.1115/1.2910301
  5. Manoha, E., 1996, "Wall Pressure Wavenumber- Frequency Spectrum Beneath a Turbulent Boundary Layer Measured with Transducers Calibrated with an Acoustic al Method," Proceedings of the ASME Symposium on Flow Noise Modeling, Measurement, and Control, Noise Control and Acoustics, Vol. 11, pp. 21-35.
  6. Chase, D. M., 1987, "The Character of the Turbulent Wall Pressure Spectrum Subconvective Wavenumbers and Suggested Comprehensive Model," J. Sound and Vib., Vol. 112, No. 1, pp. 125-147. https://doi.org/10.1016/S0022-460X(87)80098-6
  7. Manoha, E., 1996, "The Wavenumber-Frequency Spectrum of the Wall Pressure Fluctuations Beneath a Turbulent Boundary Layer," Proceedings of AIAA Aeroacoustics Conference, May 6-8, State College, PA, American Institute of Aeronautics and Astronautics, AIAA Paper 96-1758.
  8. Abraham, B. M. and Keith, W. L., 1996, "Direct Measurements of Turbulent Boundary Layer Wall Pressure Wavenumber-Frequency Spectra," Proceedings of the ASME Symposium on Flow Noise Modeling, Measurement, and Control, Noise Control and Acoustics, Vol. 22, pp. 177-187.
  9. Abraham, B. M. and Cipolla, K. M., 2001, "Experimental Measurement of the Turbulent Boundary Layer Wall Pressure Beneath a Porous and Compliant Coating," ASME FEDSM 2001-18207.
  10. Lee, I, Kulik, V. M., Boiko, A. V., Chun, H. H., 2009, "Water-Tunnel Measurement of the Drag-Reducing Effect of Compliant Coating," World Academy of Science, Engineering and Technology, Vol. 55, pp. 588-592.
  11. Kulik, V. M., 2012, "Action of a Turbulent Flow on a Hard Compliant Coating," International Journal of Heat and Fluid Flow, Vol. 33, pp. 232-241. https://doi.org/10.1016/j.ijheatfluidflow.2011.10.003
  12. S. Lee, H.-J. Kim, 1999, "Experimental Study on Wall Pressure Fluctuations in the Turbulent Boundary Layer on a Flat-Plate," Trans. of the KSME B, Vol. 23, No. 6, pp. 722-733. (in Korean)
  13. Bendat J. S. and Piersol A. G., 1991, Random Data : Analysis and Measurement Procedure, 2nd Ed. John Wiley & Sons
  14. Jeon, W. P. and Kang, S. H., 1995, "Measurement of Transitional Boundary Layer on a Flat Plate Using a Computational Preston Tube Method," Experiments in Fluids, Vol. 20, pp. 29-37. https://doi.org/10.1007/BF00190595
  15. Jeon, W. P., 1994, "Measurements of Transitional Boundary Layer on a Flat Plate in Wakes," Ph.D. thesis. Univ. Seoul, Kor.
  16. Jeon, W.P. and Kang, S. H., 1995, "Measurement of Wall Shear Sress in Transitional Boundary Layer on A Flat Plate Using Computational Preston Tube Method," Trans. of the KSME B, Vol 19, No. 1, pp. 240-250. (in Korean)
  17. Kang, S. H., Yoon, M. S. and Jeon, W. P., 1994, "Measurement of Wall Shear Stress Using Preston Tubes," Trans. of the KSME B, Vol 18, No. 7, pp. 1873-1880. (in Korean)
  18. Will, J. A. B., 1970, "Mesurments of Wave Number/Phase Velocity Spectrum of Wall Pressure Beneath a Turbulent Boundary Layer," J. Fluid Mech., Vol. 45, pp. 65-90.
  19. Finnigan, J., 2000, "Turbulence in Plant Canopies," Annu. Review Fluid Mech. Vol. 32, pp.519-571. https://doi.org/10.1146/annurev.fluid.32.1.519
  20. Zagni, A. F. E. and Smith, K. V. H. 1976, "Channel Flow over Permeable Beds of Graded Spheres," J. Hydraulics Division, Vol. 102, pp. 207-222.
  21. Zippe, H. J. and Graf, W. H., 1983, "Turbulent Boundary-Layer Flow over Permeable and Non-Permeable Rough Surfaces," J. Hydraulic Research, Vol. 21, No. 1, pp. 51-65. https://doi.org/10.1080/00221688309499450