Energy extraction from water waves using a moving piezoelectric plate

Different techniques have been proposed to convert the sea energy ( wave and current) to useful thrust or useful electrical energy. Here, the application of a moving piezoelectric flexible plate for energy extraction from sea waves is discussed. The hydrodynamics of a piezoelectric flexible submerged plate close to a free surface that is exposed to uniform flow velocity and either a head or following incoming harmonic surface wave is studied analytically. Using a continuous vortex sheet of oscillating strength and proper image system to represent the effect of the plate and the free surface on the flow field, we solve for the fluid-structure-electric interaction. The energy harvesting efficiency of the piezoelectric plate is investigated, and it is shown how the resistance and inductance characteristics of the plate along with the Froude number and the bending flexibility of the plate affect the energy extraction efficiency of the system and the optimal parameters are identified. The oscillating mode shape for most efficient cases are examined, and the importance of the moving velocity on the system energy conversion will be compared over a range of parameters.