Hydrodynamic analysis of oscillating water column in the presence of seabed undulations

Abstract

The present numerical investigation evaluates the significance of seabed undulations on the efficiency of an oscillating water column (OWC) device. The proposed physical problem is formulated in a two-dimensional Cartesian coordinate system under the framework of linearized potential flow theory. The numerical model based on the dual-boundary integral equation method (DBEM) is employed to solve the boundary value problem (BVP), and the study presents the hydrodynamic coefficients of the OWC device in the presence of a composite wavy seabed. Various effects such as the effect of seabed undulations, OWC configuration, chamber spacing, partial rotation of lip-wall, and lip-wall draft on the system radiation coefficients (i.e., wave energy capturing efficiency, radiation susceptance, and conductance) and wall force coefficient is presented against the relative wave frequency. The numerical results indicate that the efficiency of OWC is a trivariate function, which depends upon incident wave frequency, lip-wall rotation, and chamber spacing. The comparative study between various types of OWC devices (i.e., lip-wall configurations) is reported against relative wave frequency in the presence of bottom undulations. The peak performance of OWC is plausible using the resonance mechanism concept when the chamber spacing is moderate and lip-wall is either seaside horizontal or seaside partially inclined.