Performance characteristics of flapping foil flow energy harvester that mimics movement of swimming fish

Abstract

Many fish swim using various kinematic patterns of head and tail combinations to change their body posture, which reduces drag while swimming. This study proposes a new method to improve the energy-harvesting performance of a flapping foil by actively controlling the combined movements of the leading- and trailing-edge flaps. These movements allow the foil to deform to a shape with preferable hydrodynamic performance during the flapping motion inspired by fish swimming modes. The study employs two-dimensional (2D) computational fluid dynamics (CFD) simulations to investigate the effect of the forced oscillation of a leading-edge flap on the energy-harvesting performance of a flapping foil. Consequently, the optimal combination of operating parameters of the leading-edge flap leading to greater efficiency and an apparent increase in power production from the flapping foil can be determined. Therefore, the energy-harvesting performance of a flapping foil with dynamic leading- and trailing-edge flaps was investigated numerically. The results suggest that synchronized movement between the leading- and trailing-edge flaps, which mimic the movement of live fish, can increase the camber of the foil and effectively manage the boundary layer by adjusting the frequency and amplitude of the oscillations, thereby generating elevated hydrodynamic forces acting on the foil. Therefore, the proposed flapping foil with swinging leading- and trailing-edge flaps can exhibit superior energy-harvesting performance than its conventional alternative across the full spectrum of operations.