Performance evaluation and optimal design for passive turbulence control-based hydrokinetic energy harvester using EWM-based TOPSIS

Passive turbulence control (PTC) in the form of square-shaped rods (SSR) is applied to improve the performance of the flow-induced vibration (FIV)-based energy harvester. The influence of SSR installation positions (θ) on the mechanical power and hydroelastic efficiency of SSR-cylinders is studied experimentally. Vortex-induced vibration (VIV) and VIV-galloping coupling modes are observed in this research. It is found that the SSR-cylinder with θ = 150° (VIV-galloping coupling) achieves the highest mechanical power, while the SSR-cylinder with θ = 180° (VIV) attains the highest hydroelastic efficiency. To evaluate the performance of energy harvesting and find the optimal design of the oscillator, the technique for order of preference by similarity to ideal solution (TOPSIS) is employed. The TOPSIS method considers both the average and maximum values of mechanical power and hydroelastic efficiency, with data-driven and adaptive weights estimated using the entropy weight method (EWM). It is indicated that the SSR installed at 150° obtains the optimal performance in a wide flow velocity range, followed by 140° and 70°. Finally, the effectiveness of the optimal design is validated by comparing it with other harvesters and the rationality of the proposed EWM-based TOPSIS method is analyzed in detail.