No abstract

The aeroelastic galloping of a cantilever with attached prism has recently attracted the attention of several researchers as a way to harvest energy from an airstream. This arrangement is not entirely analogous to that of classical Transverse Galloping (TG) since the instantaneous attitude of the galloping body (prism) with respect to the incident flow depends both on the velocity of the galloping body and wind speed (like in TG) but also on the rotation angle at the cantilever free end. A new governing parameter emerges, namely the ratio of the cross-section length of the prism to the beam length S, and its effect on the galloping dynamics and power output needs to be studied. To this end, a theoretical model is here developed where the influence of & is considered.

No abstract

This paper presents a theoretical study of the coupling between a vortex-induced vibration (VIV) cylindrical resonator and its associated linear electromagnetic generator. The two-equation mathematical model is based on a dual-mass formulation in which the dominant masses are the stator and translator masses of the generator. The fluid–structure interaction implemented in the model equations follows the so-called ‘advanced forcing model’ whose closure relies on experimental data. The rationale to carry out the study is the fact that in these types of configurations there is a two-way interaction between the moving parts in such a way that their motions influence each other simultaneously, thereby affecting the energy actually harvested. It is believed that instead of mainly resorting to complementary numerical simulations, a theoretical model can shed some light on the nature of the interaction and, at the same time, provide scaling laws that can be used for practical design and optimization purposes. It has been found that the proposed configuration has a maximum hydrodynamic to mechanical to electrical conversion efficiency (based on the VIV resonator oscillation amplitude) of 8%. For a cylindrical resonator 10 cm long with a 2 cm diameter, this translates into an output power of 20 to 160 mW for water stream velocities in the range from 0.5 to 1 m s−1.