Quasi-static model for the aerodynamic instability of yawed circular cylinders

Quasi-static hypotheses have been often adopted to model wind forces on moving cylinders in cross-flow and to study instability conditions of rigid cylinders supported by visco-elastic devices. Recently, much attention has been devoted to the experimental study of inclined and/or yawed circular cylinders detecting peculiar dynamical phenomena such as galloping-like instability, but, at the present state-of-the-art, no mathematical model is able to recognize or predict satisfactorily this behaviour. The present paper presents a generalization of the quasi-static theory for the definition of the wind forces on yawed and inclined circular cylinders. The proposed model is able to replicate experimental behaviours and to predict the galloping instability phenomena observed during a series of recent wind-tunnel tests