Comportamento aeroelastico di stralli asciutti e ghiacciati: similitudini e differenze

Galloping vibrations due to critical Reynolds number effects in inclined flow conditions, have been identified as a potential problem for stay cables. These vibrations are governed by parameters determining a complex aerodynamics: effects of cable irregularities (surface roughness, section distortion and axis curvature) and dependency on climatic conditions (dry, ice accreted and wet stay cable surface). This paper deals with the differences between the aerodynamics of dry and ice accreted stay cables. First, the mean along-wind and across-wind coefficients obtained through climatic wind tunnel tests are presented. Then, the aerodynamic coefficients are used to predict the aerodynamic instabilities using 1 DoF and tuned and detuned 2 DoFs models taken from the literature. Comparison of the results highlights that climatic condition and frequency tuning (in the 2 DoFs models) have a significant effect on the aerodynamic stability.