TY - GEN

T1 - Assessment of Time-Domain Models of Wave Energy Conversion Systems

AU - Kurniawan, Adi

AU - Hals, Jørgen

AU - Moan, Torgeir

PY - 2011

Y1 - 2011

N2 - Time-domain models are necessary for the analysis of wave energy conversion systems, due to the presence of nonlinearities which may not be neglected for accurate prediction of their performance and behaviour. Such nonlinearities are contributed in varying degrees by drag, Coulomb friction, fluid compressibility, and also control mechanism. In time-domain, the equations of motion for the system will contain hydrodynamic radiation terms expressed as convolution integrals due to the fre- quency dependence of the radiation coefficients. The evaluation of the convolution integral is time-consuming and is difficult to carry out by standard adaptive solvers. Hence, various approximations to the convolution integral have been proposed to avoid these problems. The purpose of this study is to systematically assess the quality of some selected time-domain models. Generic models of wave energy conversion systems will be developed, with the possibility of varying the relative importance of the nonlinear terms. The time-domain models are categorised according to the convolution approximation and the numerical integration method used. Selected assessment criteria include computation time as well as the statistics of device motions and converted power. A model is always a trade-off between efficiency and accuracy. It is hoped that this study will provide some guidelines in the choice of time-domain models suitable for simulation of wave energy conversion systems.

AB - Time-domain models are necessary for the analysis of wave energy conversion systems, due to the presence of nonlinearities which may not be neglected for accurate prediction of their performance and behaviour. Such nonlinearities are contributed in varying degrees by drag, Coulomb friction, fluid compressibility, and also control mechanism. In time-domain, the equations of motion for the system will contain hydrodynamic radiation terms expressed as convolution integrals due to the fre- quency dependence of the radiation coefficients. The evaluation of the convolution integral is time-consuming and is difficult to carry out by standard adaptive solvers. Hence, various approximations to the convolution integral have been proposed to avoid these problems. The purpose of this study is to systematically assess the quality of some selected time-domain models. Generic models of wave energy conversion systems will be developed, with the possibility of varying the relative importance of the nonlinear terms. The time-domain models are categorised according to the convolution approximation and the numerical integration method used. Selected assessment criteria include computation time as well as the statistics of device motions and converted power. A model is always a trade-off between efficiency and accuracy. It is hoped that this study will provide some guidelines in the choice of time-domain models suitable for simulation of wave energy conversion systems.

KW - bond graph

KW - time-domain simulation

KW - wave energy

UR - http://www.ntnu.edu/documents/174596/8a074f75-91a3-490f-9770-bf3f661db05f

UR - http://www.mendeley.com/research/assessment-timedomain-models-wave-energy-conversion-systems

M3 - Conference paper

T3 - Proceedings of the 9th European Wave and Tidal Energy Conference

SP - 12

BT - Proceedings of the 9th European Wave and Tidal Energy Conference

ER -