The potential for classical galloping of a nominally smooth circular cylinder - A special case

There continues to be uncertainty in the aerodynamic excitation mechanisms causing large amplitude vibration of dry inclined cables on cable-stayed bridges. It has been suggested by several authors that effects in the critical Reynolds number range may be a source of excitation. In this paper, measured drag and lift coefficients are presented for a cylinder in the critical Reynolds number range. It is found that the lift is significant and is a consistent function of the angle of attack, despite the cylinder being nominally smooth and circular. Hence the Den Hartog criterion implies that classical galloping would occur for wind speeds in the critical Reynolds number range. Ongoing dynamic experiments on a new forced vibration rig aim to test the validity of quasi-steady theory in this situation.