On the modelling of WECs in wave models using far field coefficients
Abstract
Time domain (phase resolved) and spectral (phase averaged) wave models are the usual numerical tools for studying wave climate evolution, coastal processes and environmental impacts at regional scale. However, it is not straightforward to model a WEC or a WEC array in such models. At present there have been attempts in which the WECs are modelled as sinks and sources coefficients, these coefficients having been calibrated empirically. This method only partially addresses the underlying physics.
In contrast, this paper presents a method which is seen as superior because it addresses better the problem, particularly in case of oscillating WECs or OWCs. The method couples the BEM approach and phase resolved or phase averaged approaches. It makes use of far field coefficients from BEM (also know as the Kochin function) which can be integrated in wave propagation models.
First, the theory for the calculation of the far field coefficients is recalled as well as the underlying assumptions. Then, a methodology for coupling with phase resolved wave models is proposed. It makes use of domain decomposition. Comparison of results obtained with the proposed coupled method with direct approach shows excellent agreement, which confirms the potential of the method. Eventually, a methodology for coupling with spectral wave models is envisaged.
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