Interference galloping of upstream member of a pair of circular cylinders

✍ Scribed by A. Bokaian

• Book ID: 104154521
• Publisher: Elsevier Science
• Year: 1987
• Tongue: English
• Weight: 578 KB
• Volume: 117
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1016/s0022-460x(87)80063-9

✦ Synopsis

A quasi-steady theory is described for predicting the galloping motion of an elastic circular cylinder, with oscillations constrained to a plane normal to the incident flow, as induced by the vicinity of a rigid parallel circular cylinder placed inside the wake. The mathematical model predicts that the mean (time-invariant) position of the vibrating body varies with the free-stream dynamic pressure and the lift forces except when the downstream rigid cylinder is exactly in-line. An increase in the cylinder mass or damping causes the galloping to occur at a higher flow velocity. Hoveever for in-line arrangement, this increase is found to have no effect at all on the variation of the reduced (relative) oscillation amplitude with the twice reduced flow velocity and also on that of the twice reduced motion frequency against the reduced vibration amplitude, the latter variation being only a function of lift forces. The theory indicates that the galloping instability occurs only when the rigid body is in the near wake of the flexible one.