Showing papers on "Vortex-induced vibration published in 1980"

The forces on sharp-edged cylinders in oscillatory flow at low Keulegan–Carpenter numbers

Abstract: This paper describes an analysis of the forces induced by separation and vortex shedding from sharp-edged bodies in oscillatory flow at high Reynolds number. The analysis which is valid for the case of small oscillations of the fluid is compared with experimental data obtained at fairly low Keulegan–Carpenter numbers.The main conclusions of this paper were presented at the International Symposium on Wave Induced Forces on Structures at Bristol, 1978.

Measurement of Aerodynamic Power Associated with Vortex-Induced Vibration of Electrical Transmission Lines

Abstract: Prediction of the amplitude of vortex -induced vibration (aeolian vibration) of electrical transmission lines is based on knowledge of the aerodynamic power transferred to a circular cylinder oscilating in a cross flow. Methods for the measurement of aerodynamic power and the available data are reviewed. The paper reports new data obtained by direct measurement of the unsteady pressure distribution on a cylinder undergoing forced sinusoidal oscillation in a cross flow with a Reynolds number range of 3000 to 4000. The measurements of aerodynamic power are in agreement with those obtained by Farquharson and McHugh with a different technique.

Vortex Shedding from Stationary and Vibrating Bluff Bodies in a Shear Flow.

Abstract: : If a fluid is in relative motion past a stationary bluff, or unstreamlined, structure and the vortex shedding frequency approaches one of the natural frequencies of the structure, then resonant flow-induced oscillations of the structure can occur when the damping of the system is sufficiently low. These resonant oscillations are accompanied by a 'lock-on' or capture of the vortex shedding frequency by the vibration frequency over a range of flow speeds, and this lock-on effect causes the wake and the structure to oscillate in unison. The periodic lift and the mean drag forces are amplified as a result of the vibrations, and changes in these fluid forces are closely related to the changes that occur in the flow field in the near wake of the body. Many practical ocean and wind engineering situations involve lightly-damped structures that are located in flows of air or water that are nonuniform along the length of the structure. The primary difference between a uniform flow and a shear flow is the presence and added complexity, in a shear flow, of vorticity whose vector is normal to the plane of the flow. When the incident flow approaches the body this vorticity is turned into the flow direction and interacts with the vortices which are shed from the body into the wake.