Influence of variation in dynamic parameters of the flexible hydrofoil on energy harvesting performance

The flexible hydrofoil represents a promising tidal energy harvesting device, known for its environmentally friendly attributes. Understanding the intricacies of its energy harvesting mechanism and analyzing the impacts of key parameters are essential prerequisites for achieving refined design and optimization. In pursuit of this objective, this paper conducts a comprehensive numerical analysis. A numerical model is developed, focusing on a flexible tail hydrofoil that operates under the fully-passive model and incorporates the crucial aspect of fluid-structure interaction (FSI). With the established model, such as heave damping, pitch damping, heave elasticity coefficient, and pitch elasticity coefficient, various dynamic parameters are delved into the influence on energy harvesting performance. The FSI phenomenon occurring between the hydrofoil and the fluid flow are analyzed. Due to the influence of the tail flexibility of the oscillating foil, the trailing edge vortex is generated and the intensity increases. This phenomenon affects the generation and development of the leading-edge vortex, the magnitude of the lift and the synchronization of motion. Through this optimization process, the oscillating hydrofoil attained an average efficiency of 37.8 % and an average energy harvesting power coefficient of 1.56.