Turbulence effects on the post-critical response of flutter-based generators

Workable power generators based on flutter-induced mechanical vibrations require low onset flow speed, large operative range and high capability to extract energy from the flow. Along this line, the results obtained for a configuration with a small eccentricity of the mass centre downstream of the elastic axis, the latter fixed at the upstream quarter-chord, showed that even a high level of turbulence intensity of about 15%, with a turbulence scale of about twice the section-chord of the model, has little influence on the system response. The self-sustained oscillations are also preserved in the case of high levels of heaving damping, allowing for the extraction of large amounts of energy. Finally, highly turbulent flows can even trigger the flutter instability in the sub-critical range of flow speed due to buffeting excitation, widening in this way the operative range of the generator.