Hydrodynamic Analysis of Arrays of General Bodies

Abstract

Wave energy is one of the world’s largest sources of renewable energy. However, wave energy farms are in an early stage of development and relevant research in this field has not produced a general agreement on design approach. Many research articles have been published analyzing optimal geometry of a singular wave energy converter (WEC) or the arrangement of a narrow range of varied geometry. This thesis seeks to expand on this research to study the effects of both WEC arrangement and varied body geometry. An optimal combination of WEC geometry and array configuration to maximize energy absorption from scattered and radiated wave interactions between bodies can be determined using computational methods. In order to lay the groundwork to accomplish this, a partial wave decomposition model was developed to describe wave-body interaction of a body of general shape. Hydrodynamic behavior was modeled using potential flow and linear wave theories, in line with other research in this area. Bodies of varied shapes were modelled using computer aided design (CAD) software. The hydrodynamic response of the isolated body problem was subsequently analyzed using the WAMIT boundary element method (BEM) program. Resulting velocity potentials, excitation forces, and other hydrodynamic quantities were then processed using a partial wave mathematical model to determine each body’s unique diffraction and force transfer matrices. These characteristic quantities were then input into a multiple wave scattering interaction in-house program to analyze the system response in various configurations. The power gain of these arrays was studied to determine the magnitude of power absorption increase relative to the body in isolation. The results were analyzed to determine arrays and body geometry designs that produce improved system response and overall WEC efficiency.