Enhancing energy harvesting capability through analysis of flow-induced vibrations in double sprung circular cylinders exposed to turbulent flow: Influence of incidence angle

The current study explores the potential for energy harvesting arising from vortex-induced and wake-induced vibrations of two circular cylinders. These cylinders are elastically mounted and exposed to turbulent flow, allowing them to undergo free oscillations. Their relative orientation, determined by the incidence angle, ranges from zero to ninety degrees. To analyze this phenomenon, we employ a finite volume methodology for computational analysis to calculate the Reynolds-averaged governing equations. Additionally, we use the explicit integration method to solve the structural dynamics equations. Our numerical analysis reveals that the upstream cylinder uniquely demonstrates vortex-induced vibration, while the downstream cylinder experiences wakeinduced vibration, especially at lower incidence angles. Interestingly, as the incidence angles increase, the wake-induced vibration in the downstream cylinder diminishes, and its vibration response aligns with that of the upstream cylinder. Furthermore, the power profile of the upstream cylinder corresponds to the progression of displacement amplitude. In contrast, for the downstream cylinder, at lower incidence angles, the maximum power increases with rising reduced velocity. However, at higher angles, the power behavior resembles that of the upstream cylinder. We determine that the optimal incidence angle for maximizing harvested power is 8 = 30 degrees, resulting in a total root mean square (RMS) of 5.83W. This represents a substantial increase of 548% compared to the combined power of two separate cylinders. The second most effective angle is 8 = 15 degrees, yielding a total RMS of 4.75W and a 375% increase, while 8 = 0 degrees occupies the third position, providing a total RMS of 3.53W and a 293% increase.