Effect of damping on galloping of circular cylinders

Abstract

Galloping motion has long been differentiated from other flow-induced motions like VIV and flutter based on the asymmetry of the flow present causing instability. Galloping instabilities can occur for circular cylinders due to proximity to a boundary or asymmetric cross-sections from strakes or other flow interference. The response of a bluff body due to galloping instabilities is still an active area of research. For VIV, such parameters as variable added mass term [1] and a damping parameter c* [2] have been introduced. This paper demonstrates that these parameters have the potential of being applied to galloping to model it as a distinct resonance phenomenon from other flow-induced motions. Additionally, it is demonstrate that the amplitudes of motion, variable added-mass, and lift are very sensitive to the added damping coefficient, but the initiation of galloping remains largely dependent on the natural frequency of the cylinder with little sensitivity to the damping.