Effects of Hydrodynamic Coupling on Energy Extraction Performance of Wave Energy Converter Arrays

Document Type

Conference Proceeding

Publication Date

1-7-2019

Department

Department of Mechanical Engineering-Engineering Mechanics

Abstract

Wave energy converter (WEC) buoys can be used for supplying electrical power for both terrestrial and marine energy grids. Marine applications include persistent sensing and refueling Underwater Autonomous Vehicles (UAVs). A WEC array is an attractive solution for marine energy grids where scalability is important, since evolving load requirements can be accommodated by adding or removing WECs from the array. The design space for a WEC array has many variables including inter-WEC spacing, individual WEC output capacity, WEC type, array geometry and the control approach[l]. Hydrodynamic decoupled analyses facilitate decentralized control, but miss a potential opportunity to exploit the hydrodynamic coupling of a more tightly packed array [2] [3]. A compact array model, parameterized with a non-dimensional WEC packing ratio, was proposed by Garnaud and Mei [1]. This paper extends those results to include the hydrodynamic coupling between individual WECs in the array showing an increase in the theoretical energy extraction.This work considers a 25-WEC, compact array example. The hydrodynamic radiation coefficients were generated using WAMIT (Wave Analysis MIT) and were incorporated into the dynamic equations introduced by Garnaud and Mei. An energy extraction efficiency metric, considering the energy dissipated due to the waves reflected by and transmitted through the array, was used to quantity the effect of the added terms. Incorporation of the hydrodynamic terms showed an increase of up to 28% in the low frequency range. This is important for wave energy conversion as it corresponds to waves with higher speeds and wavelengths.

Publisher's Statement

© 2018 IEEE.

Publication Title

OCEANS 2018 MTS/IEEE Charleston, OCEAN 2018

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