ABSTRACT

This paper investigates wave reflection characteristics induced by a piston-type porous (PTP) wave energy converter, consisting of a solid wall, a vertical porous plate, a transmission bar, a rigid block constrained by rollers, a spring and a damper. The work also researches the force exerted on the porous plate and the response of the PTP wave energy converter. This study subjects the wave energy converter to a dynamic loading external source from the wave attack and uses a mathematical model with a single degree of freedom (SDOF) system to simulate the dynamic system. A linear wave theory governs the whole fluid domain, divided into two regions by the vertical porous plate. Darcy's law is also applied in the porous plate. Finally, this investigation employs eigenfunction expansion to obtain the solution. The current study conducts a series of numerical experiments, including the reflection coefficient, the added-mass coefficient, wave force acting on the porous plate, and converter responses.

INTRODUCTION

An important characteristic of sea waves is their high energy density, which is the highest among renewable energy sources. To capture energy from sea waves, it is necessary to intercept waves with a structure that will react in an appropriate manner to wave forces applied to it. Previous researchers have developed different wave energy converters to use this energy. Recent decades have seen an increased interest in using permeable structures to control waves. Chwang (1983) investigated free surface gravity waves produced by a horizontally oscillating porous plate. This work has been applied to several recent studies on porous breakwaters. They found that the reflected wave amplitude reduced to its minima, if the distance between the porous barrier and the chamber end wall was equal to a quarter-wavelength plus a multiple of half-wavelength of the incident wave.

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