Analytical and computational approach for studying the interaction between waves and cylindrical wave energy converters oscillating in two modes

A4 Conference proceedings


Internal Authors/Editors


Publication Details

List of Authors: Heikkinen HK, Lampinen MJ, Boling JM
Editors: L. Eca, E. Onate, J. Garcia, T. Kvamsdal, P. Bergan
Place: Barcelona
Publication year: 2011
Publisher: International Center for Numerical Methods in Engineering (CIMNE)
Book title: Computational Methods in Marine Engineering IV
Start page: 413
End page: 425
Number of pages: 13
ISBN: 978-84-89925-79-3


Abstract

Ocean wave energy may be recovered by oscillating wave energy converters. The energy converter studied in this work is a horizontally orientated cylinder which may be placed at different depths in the sea. The cylinder can oscillate in horizontal and vertical directions and transfer mechanical energy forward by hydraulic cylinders. To study the interaction between the waves and the converter, we have used potential flow theory separately for both the waves and the oscillating cylinder, and then combined these potential functions by using the principle of superposition. Combined potential flow fields, together with Euler's equations, enable us to obtain the pressure distribution around the cylinder. When knowing the pressure distribution, both the force upon the cylinder, and the net mechanical power transferred from the waves to the moving cylinder, can be calculated. With this model we have analyzed several interesting topics which affect the efficiency of the wave energy converter. The phase shift is the most important parameter - with the phase shift pi/2 the best efficiency 0.5 was achieved. To achieve the right phase shift for different waves is essential due to the power capture. Furthermore it is shown that feedback control is necessary for keeping the phase shift constant. Also the cylinder radius has a great effect on the efficiency. The other important parameters studied in this work were the wave height and the wave period.


Keywords

Cylinder, Horizontal and Vertical Oscillations, Phase Shift, Wave Energy Converter

Last updated on 2019-19-10 at 03:05