Journal ArticleDOI
Sinusoidal flow relative to circular cylinders
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In this paper, the motions of vortices around single cylinders and around pairs of cylinders in relative sinusoidal flow are investigated using simultaneous flow visualization and force measurements, the vortex motions are related to the fluid-induced lift and in-line forces.Abstract:
The motions of vortices around single cylinders and around pairs of cylinders in relative sinusoidal flow are investigated in this paper. Using simultaneous flow visualization and force measurements, the vortex motions are related to the fluid-induced lift and in-line forces. For the single cylinder, several repeatable patterns of vortex shedding are identified within particular ranges of flow amplitude. The process of pairing of vortices from a previous half cycle with those in a present half cycle is fundamental to all the patterns. Visualization is shown to be more effective in a reference frame which is fixed with respect to the undisturbed fluid rather than with respect to the cylinders. For this reason, the examples of vortex motions are taken from a rig in which vertical cylinders are oscillated in a tank of fluid. By oscillating a pair of cylinders over a range of gaps, orientations and amplitudes, it is found that the vortex-shedding patterns identified for a single cylinder can synchronize either in phase or in antiphase between the two cylinders. Such observations help to explain how lift and in-line forces are influenced by cylinder proximity and in some cases these forces are significantly magnified. Force coefficients are evaluated for both the single cylinder and the pair of cylinders.read more
Citations
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Vortex formation in the wake of an oscillating cylinder
TL;DR: In this paper, it was shown that the acceleration of the cylinder each half cycle induces the roll-up of the two shear layers close to the body, and thereby the formation of four regions of vorticity each cycle.
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The effect of two degrees of freedom on vortex-induced vibration at low mass and damping
TL;DR: Although there are a great many papers dedicated to the problem of a cylinder vibrating transverse to a fluid flow, the authors observes a rather dramatic departure from previous results, which would suggest a possible modification to offshore design codes.
Journal ArticleDOI
Force on a circular cylinder in viscous oscillatory flow at low Keulegan—Carpenter numbers
TL;DR: In this article, the in-line force coefficients for circular cylinders in planar oscillatory flows of small amplitude were compared with the theoretical predictions of Stokes (1851) and Wang (1968).
Journal ArticleDOI
A numerical simulation of vortex shedding from an oscillating circular cylinder
TL;DR: In this article, a physically consistent method is used for the reconstruction of velocity fluxes which arise from discrete equations for the mass and momentum balances, and a comparison of phase-averaged velocity vectors between measurements and predictions is presented.
Journal ArticleDOI
Scour Around Vertical Pile in Waves
TL;DR: In this article, the authors present the results of an experimental investigation on scour around piles exposed to waves, including bed shear-stress measurements and a flow visualization study, based on the present data, a design equation is established, relating the scour depth to the Keulegan-carpenter number.
References
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Journal ArticleDOI
The Force Exerted by Surface Waves on Piles
Journal ArticleDOI
Forces on cylinders and plates in an oscillating fluid
G.H. Keulegan,L.H. Carpenter +1 more
Journal ArticleDOI
Interference between two circular cylinders; Series of unexpected discontinuities
M.M. Zdravkovich,D.L. Pridden +1 more
TL;DR: In this paper, the authors investigated the effect of different flow patterns on the front and base pressures of two cylinders arranged side-by-side to the approaching flow and found that the biased flow was bistable causing a change over at irregular intervals.
Journal ArticleDOI
The forces on sharp-edged cylinders in oscillatory flow at low Keulegan–Carpenter numbers
TL;DR: In this article, an analysis of the forces induced by separation and vortex shedding from sharp-edged bodies in oscillatory flow at high Reynolds number is presented. But this analysis is only valid for the case of small oscillations of the fluid.
Journal ArticleDOI
Sinusoidal flow past a circular cylinder
D.J. Maull,M.G. Milliner +1 more
TL;DR: In this article, the forces normal and transverse to the flow direction have been measured as a function of time and the interdependence of the two forces and the production and movement of vortices in the flow has been established.
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