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

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: ℓ = 0.25h, 0.5h, and 0.75h, where h 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 ℓ = 0.25h. In contrast, minimum effects were observed for ℓ = 0.5h and ℓ = 0.75h.