Galloping of wind-excited tower under external excitation and parametric damping

Abstract

This paper investigates the influence of combined fast external excitation and fast parametric damp-ing on the amplitude and the onset of galloping of a tower submitted to steady and unsteady wind flow. A lumped single degree of freedom model is considered and the cases where the turbulent wind activates either external ex-citation, parametric one or both are studied. The methods of direct partition of motion and the multiple scales are used to drive a slow dynamic near primary resonance. The influence of the combined excitations on the galloping is examined showing the beneficial effect on the amplitude and the onset of galloping when the excitations are introduced together.