Transient aeroelasticity of structures subjected to thunderstorm outflows

Literature is rich about studies which concern the insurgence of instability of structural systems under the action of steady flows, which have led to well-consolidated methods to assess the structural safety with regard to aeroelastic phenomena induced by synoptic winds. On the other hand, there are no clear references regarding aeroelasticity induced by the effect of thunderstorm outflows, events characterized by irregular variations of the wind speed and direction in a limited duration of time, which prevent the furnishing of a long time interval for the structure and the fluid to synchronize. This paper, based under the hypothesis of applicability of the classic strip and quasi-steady theory, illustrates a mathematical model able to consider the aeroelastic effects of thunderstorm outflows into the dynamic response of slender structures, from which the methodology for synoptic winds may be found as a particular case. After defining three different levels of analysis, applications regarding the Endless Column by Constantin Brâncuși under the action of ten thunderstorm outflows are proposed, whose outcomes are critically analysed and commented.