Hostname: page-component-cd9895bd7-gxg78 Total loading time: 0 Render date: 2024-12-28T06:19:14.906Z Has data issue: false hasContentIssue false
  • English
  • Français

Evolution of a single wake behind a pair of bluff bodies

Published online by Cambridge University Press:  20 April 2006

C. H. K. Williamson
C. H. K. Williamson
Affiliation:
Engineering Department, University of Cambridge Present address: Graduate Aeronautical Labs, CALTECH, Pasadena, CA91125, USA.
Get access Rights & Permissions [Opens in a new window]

Abstract

In this paper the flow behind a pair of bluff bodies placed side by side in a stream is studied using a variety of flow-visualization methods. Above a critical gap size between the bodies, vortex-shedding synchronization occurs, either in phase or in antiphase. It has previously been assumed that such synchronization forms a wake comprising two parallel vortex streets in phase and in antiphase respectively. In the present paper we find that two antiphase streets are indeed formed, although in-phase shedding leads to the development of a single large-scale wake. The vortices which are formed simultaneously at the cylinders rotate around one another downstream, each pair forming a ‘binary vortex’. The combined wake comprises a street of such vortices, which we term a binary vortex street. Below a critical gap size between the bluff bodies the flow becomes asymmetric. We observe in this regime certain harmonic modes of vortex shedding whereby the shedding frequency on one side of the wake is a multiple of that on the other. Again, a large-scale wake is formed downstream. The present observations lead to a new interpretation of hot-wire-frequency data from other studies in terms of the harmonic modes.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 159 , October 1985 , pp. 1 - 18
Copyright
© 1985 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

Bearman, P. W. & Wadcock, A. J. 1973 The interaction between a pair of circular cylinders normal to a stream. J. Fluid Mech. 61, 499–511.Google Scholar
Bierrman, D. & Herrnstein, W. H. 1933 The interference between struts in various combinations. NACA TR 468.
Cimbala, J. M. 1984 Large structure in the far wakes of two-dimensional bluff bodies. Ph.D. Thesis, California Institute of Technology.
Gerhardt, H. J. & Kramer, C. 1981 Interference effects for groups of stacks. J. Wind Engng & Ind. Aero. 8, 195–202.Google Scholar
Ishigai, S., Nishikawa, X., Nishimura, X. & Cho, X. 1972 Experimental study on structure of gas flow in tube banks with axis normal to the flow. Bull. JSME 15, 949–956.Google Scholar
Kamemoto, K. 1976 Formation and interaction of two parallel vortex streets. Bull. JSME 19, 283–290.Google Scholar
Kiya, M., Arie, M., Tamura, H. & More, H. 1980 Vortex shedding from two circular cylinders in staggered arrangement. Trans. ASME 102, 166–173.Google Scholar
Lamb, H. 1932 Hydrodynamics, pp. 221–223. Cambridge University Press.
Landweber, L. 1942 Flow about a pair of adjacent parallel cylinders normal to a stream. David Taylor Mod. B. Rep. 485, Washington.
Preston, J. & Sweeting, N. E. 1943 An improved smoke generator for use at high Reynolds numbers. ARC R & M 2023.
Quadflieg, H. 1977 Vortex induced load on the cylinder pair at high Re. Forsch. Ing. Wes. 43, 9–18.Google Scholar
Roberts, B. W. 1962 Aeroelastic vibrations in a row of circular cylinders. Ph.D. Thesis, Cambridge University.
Spivack, H. M. 1946 Vortex frequency and flow pattern in the wake of two parallel cylinders at varied spacings normal to an airstream. J. Aero. Sci. 13, 289–297.Google Scholar
Thomas, O. G. & Kraus, K. A. 1964 Interaction of vortex streets. J. Appl. Phys. 35, 3458–9.Google Scholar
Winant, C. D. & Browand, F. K. 1974 Vortex pairing, the mechanism of turbulent mixing layer growth at moderate Reynolds number. J. Fluid Mech. 63, 237–255.Google Scholar
Zdravkovich, M. 1968 Smoke observations of the wake of a group of three cylinders at low Reynolds number. J. Fluid Mech. 32, 339–351.Google Scholar
Zdravkovich, M. 1977a Review of flow interference between two circular cylinders in various arrangements. Trans. ASME I: J. Fluids Engng 618–633.Google Scholar
Zdravkovich, M. 1977b Interference between two circular cylinders: series of unexpected discontinuities. J. Ind. Aero. 2, 255–270.Google Scholar