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An experimental study of vortex shedding behind linearly tapered cylinders at low Reynolds number

Published online by Cambridge University Press:  26 April 2006

Paul S. Piccirillo  and
C. W. Van Atta
Paul S. Piccirillo
Affiliation:
Department of Applied Mechanics and Engineering Sciences, University of California, San Diego, La Jolla, CA 92093, USA
C. W. Van Atta
Affiliation:
Department of Applied Mechanics and Engineering Sciences, University of California, San Diego, La Jolla, CA 92093, USA Also at Scripps Institution of Oceanography.
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Abstract

Experiments were performed to study vortex shedding behind a linearly tapered cylinder. Four cylinders were used, with taper ratios varying from 50:1 to 100:1. The cylinders were each run at four different velocities, adjusted to cover the range of laminar vortex shedding for a non-tapered cylinder. The flow was confirmed to consist of discrete shedding cells, each with a constant frequency. For a centrespan Reynolds number greater than 100, the dimensionless mean cell length was found to be a constant. Individual cell size was found to be roughly self-similar. New shedding cells were created on the ends of the cylinders, or in regions adjacent to areas not shedding. Successful scalings were found for both the cell shedding frequencies and their differences, the modulation frequencies. The modulation frequencies were found to be constant along the cylinder span. The shedding frequency Strouhal number versus Reynolds number curve was found to have a slightly steeper slope than the Strouhal number curve for a non-tapered cylinder. Vortex shedding was found to begin at a local Reynolds number of about 60, regardless of any other factors. End effects were found to be of little importance.

The vortex splits, which form the links between shedding cells, were found to be similar in some respects to those found by earlier investigators. Amplitude results suggested that the splits at different spanwise locations are temporally sequenced by an overall flow mechanism, a supposition confirmed by flow visualization. Wavelet analysis results showed that while the behaviour of the shedding frequencies in time was relatively unaffected by changing taper ratio, the behaviour of the modulation frequency in time was greatly affected. Comparisons with other experiments point out the universality of vortex splitting phenomena.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 246 , January 1993 , pp. 163 - 195
Copyright
© 1993 Cambridge University Press

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References

Browand, F. K. & Prost-Domasky, S. 1990 Experiment on pattern evolution in the 2-D mixing layer. In New Trends in Nonlinear Dynamics and Patterning Phenomena: The Geometry of Non Equilibrium. (ed, P. Coullet & P. Huerre). Plenum.
Browand, F. K. & Troutt, T. R 1985 The turbulent mixing layer; geometry of large vortices. J. Fluid Mech. 158, 489– 509.Google Scholar
Dallard, T. & Browand, F. K. 1993 The growth of large scales at defect sites in the plane mixing layer. J. Fluid Mech. (in press).Google Scholar
Eisenlohr, H. & Eckelmann, H. 1989 Vortex splitting and its consequences in the vortex street wake of cylinders at low Reynolds numbers. Phys. Fluids A 1, 189– 192.Google Scholar
Gaster, M. 1969 Vortex shedding from slender cones at low Reynolds numbers. J. Fluid Mech. 38, 565– 576.Google Scholar
Gaster, M. 1971 Vortex shedding from circular cylinders at low Reynolds numbers. J. Fluid Mech. 46, 749– 756.Google Scholar
Gerich, D. & Eckelmann, H, 1982 Influence of end plates on the shedding frequency of circular cylinders. J. Fluid Mech. 122, 109– 121.Google Scholar
Griffin, O. 1987 Vortex shedding from bluff bodies in shear flow: A Review. Trans, ASME J: J. Fluids Engng 107, 298– 306.Google Scholar
Hammache, M. & Gharib, M. 1989 A novel way to promote vortex shedding in the wake of circular cylinders. Phys. Fluids A 1, 1611– 1614.Google Scholar
Jespersen, D. & Levit, C, 1991 Numerical simulation of flow past a tapered cylinder. AIAA 29th Aerospace, Sciences Meeting, Reno, AIAA Paper 91– 0751.
Lewis, C. G, & Gharib, M. 1992 An exploration of the wake three dimensionalities caused by a local discontinuity in cylinder diameter. Phys. Fluids A 4, 104– 117.Google Scholar
Liandrat, J. & Moret-Bailly, F. 1990 The wavelet transform: some applications to fluid dynamics and turbulence Eur. J. Mech. B Fluids 9, 1– 19.Google Scholar
Maull, D. J. & Young, R. A. 1973 Vortex shedding from bluff bodies in shear flow. J Fluid Mech. 60, 401– 409.Google Scholar
Noack, B. R., Ohle, F. & Eckelmann, H. 1991 On cell formation in vortex streets. J. Fluid Mech. 227, 293– 308.Google Scholar
Piccirillo, P. S. 1990 An experimental study of flow behind a linearly tapered cylinder at low Reynolds number. M.S. thesis, University of California. San Diego.
Roshko, A. 1954 On the development of turbulent wakes from vortex streets. NACA Rep. 1191.Google Scholar
Slaouti, A. & Gerrard, J. H. 1981 An experimental investigation of the end effects of the wake of a circular cylinder towed through water at low Reynolds numbers. J. Fluid Mech. 112, 297– 314.Google Scholar
Van Atta, C. W. & Piccirillo, P. 1990 Topological defects in vortex streets behind tapered circular cylinders at low Reynolds numbers. In New Trends in Nonlinear Dynamics and Patterning Phenomena: The Geometry of Non Equilibrium (ed. P. Coullet & P. Huerre), pp. 243– 250. Plenum.
Williamson, C. H. K, 1989 Oblique and parallel modes of shedding in the wake of circular cylinders at low Reynolds numbers. J. Fluid Mech. 206, 579– 627.Google Scholar
Williamson, C. H. K. 1991 The natural and forced formation of ‘vortex dislocations’ in the transition to three-dimensionality of a wake. Bull. Am. Phys. Soc. 36, 2629.Google Scholar
Woo, H. G., Cermak, J. E. & Peterka, J. A. 1989 Secondary flows and vortex formation around a circular cylinder in constant-shear flow. J. Fluid Mech. 204, 523– 542.Google Scholar