Specific power input: Comparison among rigid and flexible models

The specific power input imparted by the blowing wind to an oscillating circular cylinder is a key topic in calculating aeolian vibrations of overhead transmission lines using the energy balance principle, i.e. the most common methodology used to design new lines and to dimension fittings and damping devices. The specific power input as function of the vibration amplitude was measured, during the last decades, by different research groups using different models. The obtained curves show a large dispersion of the results increasing the uncertainties in determining the vibration amplitudes. Aim of this paper is to describe the results obtained during experimental campaigns carried out at Politecnico di Milano Wind Tunnel using both flexible and rigid sectional model and to highlight the differences among the two cases in terms of vortex induced vibrations with particular reference to specific power input.