Efficient determination of nonlinear response of an array of Oscillating Water Column energy harvesters exposed to random sea waves

Abstract

This paper considers the problem of estimating the response of an array of Oscillating Water Columns (OWCs) installed in a vertical breakwater and exposed to the action of random waves. Specifically, a system model is developed based on the unsteady Bernoulli equation and on isentropic thermodynamics accounting for the air chamber, which is used for estimating the system response. The appeal of this model is that it allows simplifying considerably the determination of the hydrodynamic parameters associated with the OWC array, which are derived by relying on semi-analytical solutions of the pertinent boundary value problems. The drawback of this model is that its nonlinear terms prohibit solving analytically the equation of motion of the system. To address this issue, an approximate solution scheme based on the concept of statistical linearization is developed. In this regard, the original nonlinear system is replaced by a linear one which is optimal in a mean square sense and is used for calculating the response statistics, and the OWC energy harvesting efficiency. The usefulness and reliability of the proposed scheme are demonstrated by juxtaposition with pertinent Monte Carlo simulation data.