Francesca Lupi (Partner at Niemann Ingenieure GbG (Bochum))

Full-scale VIV measurements
on wind turbine towers

Abstract:

The presentation deals with the modelling of vortex induced vibrations using the concept of negative aerodynamic damping. Field measurements on wind turbine towers with and without nacelle are discussed. The prototypes are installed at the Østerild test center in Denmark and are equipped with pressure sensors, accelerometers and strain gauges to measure the wind load and tower response. Two met masts are available in the vicinity of the towers to measure the wind profile along the height. 

Claudio Mannini (Assistant Professor at University of Florence)

Modelling and physical interpretation
of VIV-galloping instability
of slender bluff bodies

Abstract:

For some slender bluff bodies, such as rectangular cylinders with certain side ratios, vortex-induced vibration (VIV) and transverse galloping strongly interact, giving rise to a peculiar instability that exhibits large vibrations in reduced velocity ranges where no excitation is predicted by the individual classical theories. A contribution to the understanding of this complex phenomenon has been offered by mathematical modelling through nonlinear wake oscillators. In particular, a modified version of Tamura’s model has shown its ability not only to reproduce most of VIV-galloping features observed in the experiments in both smooth and turbulent flow, but also to provide a physical interpretation of such a strong interaction.

Contact : Dr. Thomas Andrianne