Hostname: page-component-848d4c4894-x24gv Total loading time: 0 Render date: 2024-05-01T07:43:19.019Z Has data issue: false hasContentIssue false
  • English
  • Français

The flapping shear layer formed by flow separation from the forward corner of a square cylinder

Published online by Cambridge University Press:  26 April 2006

D. A. Lyn  and
W. Rodi
D. A. Lyn
Affiliation:
School of Civil Engineering, Purdue University, W. Lafayette, IN 47907, USA
W. Rodi
Affiliation:
Institute for Hydrodynamics, University of Karlsruhe, D-7500 Karlsruhe, Germany
Get access Rights & Permissions [Opens in a new window]

Abstract

The turbulent shear layer and the associated recirculation region on the sidewall formed in flow separation from the forward corner of a square cylinder have been studied with one-component laser-Doppler velocimetry. Because of vortex shedding, the flow is approximately periodic, and is treated as a separated flow undergoing largeamplitude forcing at the shedding frequency. Phase (ensemble)-averaged velocities and turbulence intensities were obtained, and a close relationship in phase and amplitude between phase-averaged turbulence intensities and gradients of phase-averaged velocity is found in much of the flow region. The similarity behaviour of the phase-averaged profiles in the shear layer as well as the streamwise growth of the shear layer are investigated. While phase-averaged velocity profiles collapse well in similarity coordinates, normalized turbulence intensities exhibit systematic deviations from similarity. Shear-layer growth also departs markedly from the linear growth law of unforced plane mixing layers. The effect of the recirculation is suggested as a possible explanation for some of these deviations. Similarities to and differences from steady and forced mixing layers, steady separated flows with recirculation, and unsteady boundary layers are discussed.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 267 , 25 May 1994 , pp. 353 - 376
Copyright
© 1994 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Cantwell, B. & Coles, D. 1983 An experimental study of entrainment and transport in the turbulent near wake of a circular cylinder. J. Fluid Mech. 136, 321–374.Google Scholar
Castro, I. P. & Haque, A. 1987 The structure of a turbulent shear layer bounding a separation region. J. Fluid Mech. 179, 439–468.Google Scholar
Cherry, N. J., Hillier, R. & Hillier, M. E. M. P. 1984 Unsteady measurements in a separated and reattaching flow. J. Fluid Mech. 144, 13–46.Google Scholar
Cousteix, J. & Houdeville, R. 1988 Effects of unsteadiness on turbulent boundary layers. Von Karman Inst. Lecture Series on Unsteady Aerodynamics, April 18–22, 1988.
Djilali, N. & Gartshore, I. S. 1991 Turbulent flow around a bluff rectangular plate. Part 1: Experimental Investigation. Trans. ASME I: J. Fluids Engng 113, 51–59.Google Scholar
Durao, D. F. G., Heitor, M. V. & Pereira, J. C. F. 1988 Measurements of turbulent and periodic flows around a square cross-section cylinder. Exps Fluids 6, 298–304.Google Scholar
Fiedler, H. E. & Mensing, P. 1985 The plane turbulent shear layer with periodic excitation. J. Fluid Mech. 150, 281–309.Google Scholar
Gaster, M., Kit, E. & Wygnanski, I. 1985 Large-scale structures in a forced turbulent mixing layer. J. Fluid Mech. 150, 23–39.Google Scholar
Ho, C.-H. & Huang, L.-S. 1982 Subharmonics and vortex merging in mixing layers. J. Fluid Mech. 119, 443–473.Google Scholar
Hussain, A. K. M. F. 1986 Coherent structures and turbulence. J. Fluid Mech. 173, 303–356.Google Scholar
Hussain, A. K. M. F. & Hayakawa, M. 1987 Eduction of large-scale organized structures in a turbulent plane wake. J. Fluid Mech. 180, 193–229.Google Scholar
Hussain, A. K. M. F. & Reynolds, W. 1970 The mechanics of an organized wave in turbulent shear flow. J. Fluid Mech. 41, 241–258.Google Scholar
Kiya, M. & Sasaki, K. 1983 Structure of a turbulent separation bubble. J. Fluid Mech. 137, 83–114.Google Scholar
Mehta, R. D. & Westphal, R. V. 1986 Near-field turbulence properties of single- and two-stream plane mixing layers. Exps Fluids 4, 257–266.Google Scholar
Okajima, A. 1982 Strouhal numbers of rectangular cylinders. J. Fluid Mech. 123, 379–398.Google Scholar
Oster, D. & Wygnanski, I. 1982 The forced mixing layer between parallel streams. J. Fluid Mech. 123, 91–130.Google Scholar
Owen, F. K. & Johnson, D. A. 1980 Measurements of unsteady vortex flowfields. AIAA J. 18, 1173–1179.Google Scholar
Perry, A. E. & Steiner, T. R. 1987 Large-scale structures in turbulent wakes behind bluff bodies. Part 1. Vortex formation processes. J. Fluid Mech. 174, 233–270.Google Scholar
Ruderich, R. & Fernholz, H. H. 1986 An experimental investigation of a turbulent flow with separation, reverse flow, and reattachment. J. Fluid Mech. 163, 283–322.Google Scholar
Simpson, R. L., Shivaprasad, B. G. & Chew, Y.-T. 1983 The structure of a separating turbulent boundary layer. Part 4. Effects of periodic free-stream unsteadiness. J. Fluid Mech. 127, 219–261.Google Scholar
Weisbrot, I. & Wygnanski, I. 1988 On coherent structures in a highly excited mixing layer. J. Fluid Mech. 195, 137–159.Google Scholar