Author:
Bearman P. W.,Obasaju E. D.
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.
Publisher
Cambridge University Press (CUP)
Subject
Mechanical Engineering,Mechanics of Materials,Condensed Matter Physics
Reference25 articles.
1. Hartlen, R. T. & Currie, I. G. 1970 Lift-oscillator model of vortex-induced vibrations.Proc. A.S.C.E. 96 (EMD),577–591.
2. Stansby, P. K. 1976 Base pressure of oscillating circular cylinders.Proc. A.S.C.E. 102 (EM4),591–600.
3. Lee, B. E. 1975 The effect of turbulence on the surface pressure field of a square prism.J. Fluid Mech. 69,263–282.
4. Obasaju, E. D. 1979 On the effects of end plates on the mean forces on square sectional cylinders.J. Ind. Aero. 5,179–186.
5. 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 .
Cited by
342 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献