Abstract
The separated shear layer in the near wake of a circular cylinder was investigated using a single hot wire probe, with special attention given to the shear layer instability characteristics. Without end plates to force parallel vortex shedding, the critical Reynolds number for the onset of the instability was 740. The present data, together with all previously published data, show that the ratio of the instability frequency fsl to the vortex shedding frequency fv varies as Re0.65, which is in agreement with the Re0.67 dependence obtained by Prasad and Williamson [1997, J Fluid Mech 333:375–402]. However, the distribution of fsl/fv and the spectra of the longitudinal velocity fluctuation (u) suggest that, on either side of Re=5,000, the shear layer exhibits lower and upper subcritical regimes, in support of the observations by Norberg [1987, publication no. 87/2, Chalmers University of Technology, Sweden] and Prasad and Williamson [1997, J Fluid Mech 343:235–265]. The spectra of u provide strong evidence for the occurrence of vortex pairing in wake shear layers, suggesting that the near wake develops in a similar manner to a mixing layer.
Similar content being viewed by others
References
Ahmed NA, Wagner DJ (2003) Vortex shedding and transition frequencies associated with flow around circular cylinder. AIAA Jl 41(3):542–544
Bloor MS (1964) The transition to turbulence in the wake of a circular cylinder. J Fluid Mech 19:290–304
Braza M, Chassaing P, Ha Minh H (1990) Prediction of large scale transition feature in the wake of a circular cylinder. Phys Fluids 2(8):1461–1471
Brede M (2004) Measurement of turbulence production in the cylinder separated shear layer using event triggered laser-Doppler anemometry. Exp Fluids 36:860–866
Brun C, Tenchine EJ, Hopfinger EJ (2004) The role of shear layer instability in the near wake behaviour of two side-by-side circular cylinders. Exp Fluids 36:334–343
Chyu C, Rockwell D (1996a) Evolution patterns of streamwise vorticity in the turbulent near wake of a circular cylinder. J Fluid Mech 320:117–137
Chyu C, Rockwell D (1996b) Near wake structure of an oscillating cylinder: effect of controlled shear layer vortices. J Fluid Mech 322:21–49
Gerrard JH (1978) The wakes of cylindrical bluff bodies at low Reynolds number. Proc Roy Soc A 288:351–382
Ho CM, Huerre P (1984) Perturbed free shear layers. Ann Rev Fluid Mech 16:365–424
Husain H, Bridges JE, Hussain F (1988) Turbulence management in free shear flows by control of coherent structures. In: Hirata M, Kasagi N (eds) Transport phenomena in turbulent flows. Hemisphere, Washington, DC, pp 111–130
Kourta A, Boisson H, Chassing P, Ha Minh H (1987) Non-linear interactions and the transition to turbulence in the wake of a circular cylinder. J Fluid Mech 181:141–161
Leung CT, Ko NWM (1982) In heat transfer 1982. Hemisphere, Munchen, pp 229–232
Lin JC, Vorobief P, Rockwell D (1995a) Three-dimensional patterns of streamwise vorticity in the turbulent near wake of a cylinder. J Fluids Struct 9:231–234
Lin JC, Towfighi J, Rockwell D (1995b) Instantaneous structure of the near wake of a circular cylinder: on the effect of Reynolds number. J Fluids Struct 9:409–418
Maekawa T, Mizuno S (1967) Flow around the separation point and in the near wake of a circular cylinder. Phys Fluids 10:S184–S186
Michalke A (1965) On spatially growing disturbances in an inviscid shear layer. J Fluid Mech 23:521–544
Mihailovic J, Corke TC (1997) Three-dimensional instability of the shear layer over a circular cylinder. Phys Fluids 9(11):3250–3257
Monkewitz P, Nguyen LN (1986) Absolute instability in the near wake of two-dimensional bluff bodies. J Fluids Struct 1:165–184
Norberg C (1987) Effects of Reynolds number and a low intensity freestream turbulence on the flow around a circular cylinder. Publication no. 87/2, Chalmers University of Technology, Sweden
Norberg C (1998) LDV measurements in the near wake of a circular cylinder. In: Bearman PW, Williamson CHK (eds) Proceedings of the ASME conference on advances in the understanding of bluff body wakes and vortex induced vibration, Washington, DC
Okamoto S, Hirose T, Adachi T (1981) The effect of sound on the vortex shedding from a circular cylinder. Bull JSME 24:45–53
Peterka JA, Richardson PD (1969) Effect of sound on separated flows. J Fluid Mech 37:265–287
Prasad A, Williamson CHK (1996) The instability of the separated shear layer from a bluff body. Phys Fluids 8:1347–1349
Prasad A, Williamson CHK (1997a) The instability of a shear layer separating from a bluff body. J Fluid Mech 333:375–402
Prasad A, Williamson CHK (1997b) Three-dimensional effects in turbulent bluff body wakes. J Fluid Mech 343:235–265
Prasad A, Williamson CHK (1997c) Three-dimensional effects in turbulent bluff body wakes. Exp Therm Fluid Sci 14:9–16
Sheridan J, Soria J, Wu J, Welsh MG (1993) The Kelvin–Helmholtz instability of the separated shear layer from a cylinder. In: Proceedings of the IUTAM symposium on bluff-body wakes, dynamics and instabilities, Göttingen, Germany, September 1992, pp115–118
Smith RA, Moon JM, Kao TW (1972) Experiments on flow about a yawed circular cylinder. ASME J Basic Eng 94:771–776
Unal MF, Rockwell D (1984) The role of shear layer stability in vortex shedding from cylinders. Phys Fluids 27(11):2598–2599
Unal MF, Rockwell D (1988a) On the vortex formation from a cylinder, Part 1. The initial instability. J Fluid Mech 190:491–512
Unal MF, Rockwell D (1988b) On the vortex formation from a cylinder. Part 2. Control by splitter plate interference. J Fluid Mech 190:513–529
Wei T, Smith CR (1986) Secondary vortices in the wake of circular cylinders. J Fluid Mech 169:513–533
Williamson CHK (1989) Oblique and parallel modes of vortex shedding in the wake of a circular cylinder at low Reynolds numbers. J Fluid Mech 206:579–627
Williamson CHK (1996) Vortex dynamics in the cylinder wake. Ann Rev Fluid Mech 28:477–539
Wu J, Sheridan J, Hourigan K, Soria J (1996) Shear layer vortices and longitudinal vortices in the near wake of a circular cylinder. Exp Therm Fluid Sci 12(2):169–174
Yamanaka G, Imaichi K, Adachi T (1973) The influence of acoustic disturbances on the mechanism in a shear layer behind a circular cylinder in airflow. DISA Inf 14:37–44
Zdravkovich M (1997) Flow around circular cylinders, vol. 1. Oxford University Press, Oxford
Acknowledgements
RAA acknowledges the continuing support of the Australian Research Council. The technical assistance of Ken Sayce is gratefully acknowledged.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Rajagopalan, S., Antonia, R.A. Flow around a circular cylinder—structure of the near wake shear layer. Exp Fluids 38, 393–402 (2005). https://doi.org/10.1007/s00348-004-0913-0
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00348-004-0913-0