TY - JOUR
TI - A time-varying parameter model of a body oscillating in pitch
AU - McCabe, A
AU - Aggidis, G
AU - Stallard, T
T2 - Applied Ocean Research
AB - Among the assumptions upon which linear time-invariant models of floating bodies are based is that the body motions are so small that any change in the body’s angular position can be disregarded. However, it is often a major design requirement of a wave energy conversion device that the response amplitude is large, thereby invalidating one of the assumptions of the linear model. In particular, the immersed geometry of a body undergoes considerable variation when it is moved in pitch. With regard to this we investigate the difference in performance between a quasi-linear model in which the change of immersed surface is modelled by time-varying parameters and a basic linear model in which the immersed surface is time-invariant. The time-varying parameter model is realized by interpolation between the appropriate parameter values of a set of linear time-invariant (LTI) models derived for the different immersed surfaces that occur at discrete body displacements. It is shown that the responses predicted using the time-varying parameter model are closer to those measured experimentally than those of a standard frequency-domain model. Particular improvement occurs when the responses are large, such as at or near the resonance frequency. A problem which may limit the general use of the model is also discussed.
DA - 2006/12//
PY - 2006
PB - Elsevier
VL - 28
IS - 6
SP - 359
EP - 370
UR - https://www.sciencedirect.com/science/article/pii/S0141118707000387?via%3Dihub
DO - 10.1016/j.apor.2007.05.001
LA - English
KW - Wave
KW - Modeling
KW - Hydrodynamics
ER -