Numerical simulation of vortex-induced vibration in a bladeless turbine: Effects of separation distance between tandem harvesters

<p>Bladeless wind turbines are attracting attention as energy harvesters due to several conveniences like the ease of construction and suitability for operating under small wind speed. As a grouped energy generation system, it is likely the simplest configuration compared to wind farms. However, the characterization of tandem harvesters requires a deep understanding of the effects produced by the interaction of the two. Therefore, this work considered a set of two conical cylinders representing tandem harvesters, which lie on the bottom of a wind tunnel and were subjected to resonance conditions. The attention focused on evaluating the effects of separation distance between conical cylinders by three distances: $\ell$ = 0.25<italic>h</italic>, 0.5<italic>h,</italic> and 0.75<italic>h</italic>, where <italic>h</italic> is the cylinder's total height. Oscillation due to vortex shedding was numerically predicted. The analysis centered on the fluid-structure interaction in pairs of wind generators subjected to wind-induced resonance, and how the distance between them affects their oscillation. Experimental data of cylinder vibration measured in a wind tunnel served to validate the numerical results. The results showed strong effects of the wake on the second cylinder placed downstream from the first one for a distance $\ell$ = 0.25<italic>h</italic>. In contrast, minimum effects were observed for ℓ = 0.5<italic>h</italic> and ℓ = 0.75<italic>h</italic>.</p>