On the forces transmitted to a vibrating cylinder by a blowing fluid

Computational Analysis of Aeolian Conductor Vibration With a Stockbridge-Type Damper

“…The extrapolated region of the plot indicates that the amount of wind energy input begins to decrease at A/D +0)5. Qualitatively, this is consistent with the wind-tunnel data of Diana & Falco (1971). Hence, use of the extrapolated portion of the curve in Figure 3 may be justi"ed.…”

“…It is further postulated that lock-in occurs at this frequency along the entire conductor span. From wind-tunnel experiments (Diana & Falco, 1971) on the aeolian vibration of a rigid cylinder in a uniform #ow, it is known that the vortex-induced lift force as well as the motion vary harmonically at steady state. Based on this "nding and the postulate, it is hypothesized that, during the steady-state aeolian vibration of a conductor in a uniform wind, the local vortex-induced lift force is harmonic in time.…”

“…Wind-tunnel experiments, in which the wind power input was measured during the aeolian vibration of a circular cylinder, have been performed by many investigators, including: Bate & Callow (1934), Farquharson & McHugh (1956), Diana & Falco (1971), Macdonald et al (1989) and Brika & Laneville (1993). The wind power input is de"ned as the wind energy transferred to the cylinder over one cycle of vibration divided by the period of vibration.…”

“…As a consequence of these e!ects, the cylinder may experience a signi"cant level of vibration. Diana & Falco (1971) measured the lift force that acts during the aeolian vibration of a rigid cylinder in a uniform #ow. It was found that, like the displacement of the cylinder, the lift force is virtually harmonic in time at steady state.…”

“…It is noted that the wind energy input based on the data of Macdonald et al (1989) lies between the upper and lower bounds of all such data that are currently available in the literature. The upper bound corresponds to the data of Diana & Falco (1971), while the lower bound corresponds to the data of Farquharson & McHugh (1956). During aeolian conductor vibration, alternating bending stresses are created due to the cyclic motion of the conductor.…”