Novel petal-based configurations to enhance flow-induced vibration energy harvesting: numerical and experimental analysis

This study investigates the impact of incorporating petals into an FIV-based energy harvester through numerical simulations and experimental analyses. By varying petal heights (ε = 0.08, 0.16, 0.24) and placement angles (θ = 0°–150°), the research identifies optimal configurations for enhanced energy harvesting performance. Numerical results show that petal-equipped cylinders achieve significant lift coefficient increases 126.62 %, 99.31 %, and 77.19 % for high, medium, and low-height petals, respectively accompanied by reductions in Strouhal numbers, enabling efficient operation at lower velocities. Optimal petal angles range from 50° to 100°, with medium-height petals at 60° achieving the highest EFF value (50.1 %). The analysis reveals that the proposed geometry alters vortex shedding patterns from (2S) to (P + S) modes, enhancing flow-induced vibration (FIV) responses. Wake dynamics, characterized by increased turbulence kinetic energy (22 %) and circulation (55.1 %), confirm stronger vortex formations and amplified induced vibrations. Experimental tests validate numerical predictions, demonstrating displacement increases of 89.77 %, 77.72 %, and 75.92 % for medium, high, and low-height petals, respectively, and an 88.9 % improvement in maximum efficiency for the optimal case. Comparative analysis highlights the superiority of petal-equipped designs, with the ideal height ratio (ε = 0.1–0.16) and placement angle (60°) significantly outperforming alternative configurations. This study also contextualizes its findings for real-world applications, particularly in bladeless wind turbines, emphasizing the potential of compact, high-power-density designs. These results establish petal-equipped energy harvesters as promising solutions for advancing energy harvesting technologies and inspire future research and development.