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An experimental study of pressure fluctuations on fixed and oscillating square-section cylinders

Published online by Cambridge University Press:  20 April 2006

P. W. Bearman  and
E. D. Obasaju
P. W. Bearman
Affiliation:
Department of Aeronautics, Imperial College, London, U.K.
E. D. Obasaju
Affiliation:
Department of Aeronautics, Imperial College, London, U.K.
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Abstract

Measurements are presented of the pressure fluctuations acting on a stationary squaresection cylinder, with the front face normal to the flow, and one forced to oscillate, transverse to a flow, at amplitudes up to 25% of the length of a side. The range of reduced velocities investigated, 4–13, includes the vortex lock-in regime. At lock-in the amplification of the coefficient of fluctuating lift is found to be much less than that found for a circular cylinder. The variation of the phase angle, between lift and displacement, is also different from that measured on a circular cylinder, and vortex-induced oscillations are possible only at the high-reduced-velocity end of the lock-in range. At reduced velocities sufficiently far below lock-in the natural vortex-shedding mode is suppressed and vortices are found to form over the side faces at the body frequency. Intermittent reattachment occurs over the side faces and, for an amplitude of oscillation equal to 10% of the length of a side face, the time-mean drag coefficient can be reduced to 60% of its fixed-cylinder value.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 119 , June 1982 , pp. 297 - 321
Copyright
© 1982 Cambridge University Press

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References

Bearman, P. W. & Currie, I. G. 1979 Pressure-fluctuation measurements on an oscillating circular cylinder. J. Fluid Mech. 91, 661–677.Google Scholar
Bearman, P. W. & Graham, J. M. R. 1979 Hydrodynamic forces on cylindrical bodies in oscillatory flow. In Proc. 2nd Int. Conf. on the Behaviour of Offshore Structures, London, pp. 309–322.
Bearman, P. W. & Trueman, D. M. 1971 An investigation of the flow around rectangular cylinders. I. C. Aero. Rep. no. 71–15.Google Scholar
Berger, E. & Wille, R. 1972 Periodic flow phenomena. Ann. Rev. Fluid Mech. 4, 313–340.Google Scholar
Bishop, R. E. D. & Hassan, A. Y. 1964a The lift and drag forces on a circular cylinder in a flowing fluid. Proc. R. Soc. Lond. A 277, 32–50.Google Scholar
Bishop, R. E. D. & Hassan, A. Y. 1964b The lift and drag forces on a circular cylinder oscillating in a flowing fluid. Proc. R. Soc. Lond. A 277, 51–75.Google Scholar
Davies, M. E. 1975 Wakes of oscillating bluff bodies. Ph.D. thesis, Department of Aeronautics, Imperial College, London.
Davies, M. E. 1976 A comparison of the wake structure of a stationary and oscillating bluff bodies using a conditional averaging technique. J. Fluid Mech. 75, 209–231.Google Scholar
Gerrard, J. H. 1966 The mechanics of the formation region of vortices behind bluff bodies. J. Fluid Mech. 25, 401–413.Google Scholar
Hartlen, R. T. & Currie, I. G. 1970 Lift-oscillator model of vortex-induced vibrations. Proc. A.S.C.E. 96 (EMD), 577–591.Google Scholar
Lee, B. E. 1975 The effect of turbulence on the surface pressure field of a square prism. J. Fluid Mech. 69, 263–282.Google Scholar
Maskell, E. C. 1963 A theory of blockage effects on bluff bodies and stalled wings in a closed wind tunnel. A.R.C., R. & M. no. 3400.Google Scholar
Nakamura, Y. & Mizota, T. 1975 Unsteady lifts and wakes of oscillating rectangular prisms. Proc. A.S.C.E. 101 (EM6), 855–871.Google Scholar
Obasaju, E. D. 1979 On the effects of end plates on the mean forces on square sectional cylinders. J. Ind. Aero. 5, 179–186.Google Scholar
Otsuki, Y., Washizu, K., Tomizawa, H. & Ohya, A. 1974 A note on the aeroelastic instability of a prismatic bar with square sections. J. Sound Vib. 34, 233–248.Google Scholar
Parkinson, G. V. 1974 Mathematical models of flow-induced vibrations. In Flow-Induced Structural Vibrations (ed. E. Naudascher). Springer.
Pocha, J. J. 1971 On unsteady flow past cylinders of square cross-section. Ph.D. thesis, Department of Aeronautics, Queen Mary College, London.
Roshko, A. 1954 On the drag and shedding frequency of two-dimensional bluff bodies. NACA TN no. 3169.Google Scholar
Sarpkaya, T. 1978 Fluid forces on oscillating cylinders. Proc. A.S.C.E. (WW4) 275–290.
Sarpkaya, T. 1979 Vortex-induced oscillations. Trans. A.S.M.E. E, J. Appl. Mech. 46, 241–258.Google Scholar
Stansby, P. K. 1976 Base pressure of oscillating circular cylinders. Proc. A.S.C.E. 102 (EM4), 591–600.Google Scholar
Tanida, Y., Okajima, A. & Watanabe, Y. 1973 Stability of a circular cylinder oscillating in uniform flow or in a wake. J. Fluid Mech. 61, 769–784.Google Scholar
Vickery, B. J. 1966 Fluctuating lift and drag on a long cylinder of square cross-section in a smooth and in a turbulent stream. J. Fluid Mech. 25, 481–494.Google Scholar
Wawzonek, M. A. & Parkinson, G. V. 1979 Combined effects of galloping instability and vortex resonance. In Proc. 4th Int. Conf. on Wind Effects on Buildings and Structures, Fort Collins, Colorado.
Wilkinson, R. H. 1974 On the vortex-induced loading on long bluff cylinders. Ph.D. thesis, Faculty of Engineering, University of Bristol, England.