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Nonlinear hydrodynamic effects on a generic spherical wave energy converter

Citation

Bharath, A and Nader, J-R and Penesis, I and Macfarlane, G, Nonlinear hydrodynamic effects on a generic spherical wave energy converter, Renewable Energy, 118 pp. 56-70. ISSN 0960-1481 (2018) [Refereed Article]

Copyright Statement

Copyright 2017 Published by Elsevier Ltd.

DOI: doi:10.1016/j.renene.2017.10.078

Abstract

Analytical and numerical modelling techniques have been used extensively to predict the performance and power output of these devices using linear, inviscid and irrotational theory with the knowledge that nonlinear effects become relevant in extreme cases. This study applies Reynolds averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) model to simulate the diffraction and radiation problems for a single submerged spherical WEC operating in both heave and surge. Wave and device oscillation amplitudes from 30 mm to 60 mm and frequencies from 0.8 Hz to 1.2 Hz are employed to examine the fluid dynamics near the spherical WEC as the hydrodynamics deviate away from the linear regime. Results of the hydrodynamic coefficients from wave basin experiments are used to validate linear finite element and CFD models for small wave amplitudes. The nonlinear CFD model is then extended to model larger amplitudes. The hydrodynamic coefficients are here found to be amplitude dependent with free surface interactions being a key component of the deviation from linear theory. The rate of these deviations from low wave height, linear values via increasing wave heights is also found to vary with frequency. The outcomes highlight limitations in the linear approach and address the factors most important to WEC performance.

Item Details

Item Type:Refereed Article
Keywords:Computational fluid dynamics, Volume of fluid, Submerged sphere, Wave energy converter
Research Division:Engineering
Research Group:Maritime Engineering
Research Field:Ocean Engineering
Objective Division:Energy
Objective Group:Renewable Energy
Objective Field:Wave Energy
UTAS Author:Bharath, A (Mr Aidan Bharath)
UTAS Author:Nader, J-R (Dr Jean-Roch Nader)
UTAS Author:Penesis, I (Associate Professor Irene Penesis)
UTAS Author:Macfarlane, G (Associate Professor Gregor MacFarlane)
ID Code:131475
Year Published:2018
Web of Science® Times Cited:5
Deposited By:NC Maritime Engineering and Hydrodynamics
Deposited On:2019-03-19
Last Modified:2019-05-17
Downloads:0

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