McCabe, A. P. and Aggidis, George A. and Stallard, T. J. (2006) A time-varying parameter model of a body oscillating in pitch. Applied Ocean Research, 28 (6). pp. 359-370.Full text not available from this repository.
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.
|Journal or Publication Title:||Applied Ocean Research|
|Uncontrolled Keywords:||Time-varying parameter model ; Time-domain model ; Potential-flow hydrodynamics|
|Subjects:||T Technology > TC Hydraulic engineering. Ocean engineering|
|Departments:||Faculty of Science and Technology > Engineering|
|Deposited By:||Mrs Yaling Zhang|
|Deposited On:||24 Jun 2010 09:17|
|Last Modified:||30 Aug 2012 17:28|
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