An Experimental Study on Wave Forces and Pressures on an Oscillating Water Column Under Random Waves

Abstract

A partially submerged device, known as the Oscillating Water Column (OWC) device made up of a chamber with a bottom opening and air trapped at the top, can harness the wave energy. The studies on an OWC wave energy converter widely pertain to the optimization of its geometries to enhance the wave power absorption. On the other hand, limited studies deal with its survivability against wave conditions. For that purpose, a detailed experimental investigation is taken up to understand the nature and magnitude of dynamic pressures on the individual components and the total dynamic forces on the OWC device subjected to random wave incidence. A Froude scale of 1:12 is chosen for studying shoreward and seaward wave load distribution on the OWC device in terms of the non- dimensional pressure on the seaside of the front wall, rear wall pressure, air pressure, and the total horizontal and vertical wave forces. In general, force measurement increases with wavelength. In structural design of the lip wall of OWC device, the seaward exerted pressure should be considered as a critical parameter, since, it governs its stability against being pulled out towards the seaside. The ratio of total horizontal to vertical wave force is vary between 2.5 to 3. It is found that the neighborhood of the natural frequency of the system around d/Lp = 0.131, the measured wave force on the energy device is smaller due to high wave energy absorption.