Enhanced wind energy harvesting via 2DOF vortex-induced vibration and wake-galloping interaction

This paper presents a novel dual-degree-of-freedom hybrid energy harvester featuring a tunable auxiliary module, which synergistically combines vortex-induced vibration and wake-galloping mechanisms. The design aims to overcome key limitation of conventional flow-induced vibration energy harvesters and improve the energy harvesting efficiency. The theoretical model is developed and the output performance is thoroughly evaluated via wind tunnel experiments. The voltage amplitude and the operational wind speed range of the optimized design are respectively 1.6 times and 2.5 times of that of the conventional harvester without tunable auxiliary modules. Parametric analysis points out that geometric matching between two bluff bodies critically determines the output characteristics of the harvester. When the wind speed surpasses the critical wind speed of Bluff body 2, the resulting complex fluid–structure interactions between two bluff bodies lead to chaotic response and a consequent reduction in energy output. Overall, the presented harvester demonstrates considerable potential for practical applications, providing an efficient approach to harvest flow-induced vibration energy.