Bladeless wind energy conversion

In recent years, there has been a strong interest in new approaches to wind generation, with particular attention to technologies able to be profitable in small scale and reduce the visual impact linked to traditional wind turbines. Because of their relative constructive simplicity, among the various proposals many are based on aeroelastic phenomena grouped under the name of Flow-induced Vibrations, which are oscillations generated by the interaction between fluid and elastic structures. However, although these phenomena have long been studied in some areas of engineering because of their destructive effects, their actual potential for energy conversion is much debated. In this context, the aim of the thesis is to investigate the characteristics and potentialities of these fluid-elastic interactions in energy production, focusing in particular on two phenomena: vortex-induced vibrations (VIV) and galloping. In this regard, an in-depth analysis of the physical models of the two phenomena and their sensitivity to the various parameters of the system was carried out. Furthermore, a preliminary design of systems able to generate different levels of power has been proposed, in order to study their performance as the size changes. The main results of this analysis reveal that the conversion systems based on flow-induced vibrations are characterized by a poor conversion efficiency, little affected by the size of the system and considerably below that of traditional wind turbines. However, it was also highlighted how these phenomena can be induced even at low wind speeds, where traditional systems present different criticalities. As a result, the possible application of VIV or galloping-based wind energy conversion systems seems to be restricted to the power supply of isolated electronic devices and sensors.