Hydrodynamic responses of a reversed L type floating breakwater integrated with a wave energy converter impacted by extreme waves

Abstract

This research studies the hydrodynamic responses of a reversed L type floating breakwater integrated with a wave energy converter moored by a vertical pile in extreme sea states and intermediate water depth in a numerical wave tank based Navier-Stokes equations. Three wave-type representations (solitary, regular, and focus waves) of the same wave state are considered. The surface wave elevation, heave motion, wave force, impulse, wave moment on the mooring pile, moment of impulse, pressure distribution and flow field are investigated and compared. The comparison shows that different waves yield to diverse peak hydrodynamic responses. Largest wave force and moment are found in the regular wave condition, while largest heave motion, impulse and moment of impulse are obtained for the solitary wave. The pressure distribution on the bottom of the floater under the solitary wave shows a distinct character from the two others. The effect of the PTO damping parameter with the focus on the maximum wave force and moment is discussed and it is revealed that there exists an optimal PTO damping force for which the minimum wave force on the floater is obtained. This study therefore gains an insight into the hydrodynamic responses under different extreme waves.