The performance of a Wave Energy Converter (WEC) may be estimated using both physical and numerical modelling techniques. Since numerical models are often informed by, and validated against data obtained from physical models, it is important to assess the accuracy with which a prototype's behaviour is predicted by its physical model. This thesis makes such an assessment for the case of a pitching flap type WEC, by comparing the performance of Aquamarine Power's Oyster1 prototype device to that of a representative physical model. This comparison was informed by considering the device in terms of three sub-systems, namely: the flap; the incident waves; and the power take-off (PTO) system. Understanding the effects of characteristics associated with each of these sub-systems on the device's behaviour was pursued using both physical and numerical modelling techniques. As well as informing the comparison between the device's performance at each scale, the conclusions drawn from this work, particularly in relation to the modelling of sea conditions and PTO systems, are relevant to WEC modelling in general. Agreement between the device's behaviour at each scale was assessed by comparing measurements of the flap's angular position and velocity, and the power captured by the PTO. The velocity measured at prototype scale was 12% greater than that measured at model scale. The disagreement between velocity measurements directly affected agreement between power capture measurements, which were also 12% greater at prototype scale compared to model scale. Damage to the PTO cylinders meant that the device's performance was sub-optimal. Extrapolation of the comparison between the device's performance at each scale suggested that the power captured was 7% greater at prototype scale relative to model scale at magnitudes of power capture more representative of optimal performance.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:673795 |
| Date | January 2014 |
| Creators | Clabby, Darragh |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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