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

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

DOI QR Code

Large-Scale Vortical Structure of Turbulent Separation Bubble Affected by Unsteady Wake

비정상 후류가 난류박리기포의 응집구조에 미치는 영향

  • Published : 2002.09.01
Download PDF
⟨ Previous Next ⟩

Abstract

Large-scale vortical structure of a turbulent separation bubble affected by unsteady wake is essential to understand flow mechanisms in various fluid devices. A spoked-wheel type of wake generator provides unsteady wake, which modifies the turbulent separation bubble significantly by changing rotation directions and passing frequencies. A detailed mechanism of vortex shedding from the separation bubble with unsteady wake is analyzed by taking a conditional average with spatial box filtering, which spatially integrates measured signals at pre-determined wavelength. A convecting nature of the large-scale vortical structure is analyzed carefully. Spatial evolution of the large-scale vortical structure with frequency variance is also exemplified.

Keywords

References

  1. Kiya, M. and Sasaki, K., 1983, 'Structure of a Turbulent Separation Bubble,' Journal of Fluid Mechanics, Vol. 137, pp. 83-113 https://doi.org/10.1017/S002211208300230X
  2. Cherry, N.J., Hillier, R. and Latour, M.E.M.P., 1984, 'Unsteady Measurements in a Separated and Reattaching Flow,' Journal of Fluid Mechanics, Vol. 144, pp. 13-46 https://doi.org/10.1017/S002211208400149X
  3. Kiya, M. and Sasaki, K., 1985, 'Structure of Large-Scale Vortices and Unsteady Reverse Flow in the Reattaching Zone of a Turbulent Separation Bubble,' Journal of Fluid Mechanics, Vol. 154, pp. 463-491 https://doi.org/10.1017/S0022112085001628
  4. Lee, I. and Sung, H.J., 2001, 'Turbulence and Shear Flow Phenomena,Multipoint Measurement of Wall Pressure Fluctuations in a Separated and Reattaching Flow over a Backward-Facing Step,' Turbulence and Shear Flow Phenomena, June 27-29, KTH, Stockholm, pp. 411-416
  5. Lee, I. and Sung, H.J., 2000, 'Cross-Spectral Characteristics of Wall Pressure Fluctuations in Flows over a Backward-Facing Step,' Trans. of the KSME, Series B, Vol. 24, pp. 280-287
  6. Chun, K.B. and Sung, H.J., 1996, 'Control of Turbulent Separated Flow over a Backward-Facing Step by Local Forcing,' Experiments in Fluids, Vol. 21, pp. 417-426 https://doi.org/10.1007/BF00189044
  7. Chun, S. and Sung, H.J., 2002, 'Influence of Unsteady Wake on a Turbulent Separation Bubble,' Trans. of the KSME, Series B, Vol. 26, pp. 353-361 https://doi.org/10.1007/s003480100357
  8. Hwang, K.S., Sung, H.J. and Hyun, J.M., 2001, 'An Experimental Study of Large-Scale Vortices over a Blunt-Faced Flat Plate in Pulsating Flow,' Experiments in Fluids, Vol. 30, pp. 202-213 https://doi.org/10.1007/s003480000155
  9. Blake, W.K., 1986, 'Mechanics of Flow-Induced Sound and Vibration,' Academic Press