Wave Energy Converters (WECs) have been shown to offer a promising option for
power generation. The WaveCat is a moored WEC design which uses wave overtopping
discharge into a variable v-shaped hull, to generate electricity through low head
turbines. Physical model tests of the WaveCat WEC were carried out at the University
of Plymouth COAST Laboratory to determine the device reflection, transmission
and absorption coefficients. 60° and 30° wedge angles were tested, where wedge
angle is the angle between the two hulls. Motion response of the WaveCat model
was also quantified. The device heave and pitch motions were simulated using the
CFD package STAR-CCM+.
The results show the WaveCat absorption coefficient and expected power generation
is highest during the largest Hs and smallest Tp conditions tested for both wedge
angle cases. During the wave conditions that exhibit highest amount of power captured,
the device has the lowest motion responses. When at a 60° wedge angle the
device generated the highest power (0.4 W) during tests of Hs = 0.12 m and Tp =
1.09 s. When at a 30° wedge angle the device generated the highest power (1.8 W)
during tests of Hs = 0.15 m and Tp = 1.46 s which would be normal operating
conditions.
The 60° and 30° configurations showed the highest surge Response Amplitude Operator
(RAO) (0.68 and 0.79 respectively), pitch RAO (1.9 and 2.2 respectively) and
heave RAO (0.97 and 0.92 respectively) values during tests where the wavelength
is larger than the model length. Experimental responses were shown to be well
predicted by the numerical model.
The 60° configuration Capture Width Ratio (CWR) peaked at 1.5% during tests
indicating greatest efficiency. This occurred at Hs of 0.08 m and Tp of 1.09 s. The
30° configuration CWR peaked at 5.4% during tests indicating greatest efficiency.
This occurred at tests with Hs of 0.15 m and Tp of 1.46 s. At full scale the 60°
configuration produced the equivalent of 64.6 kW in conditions of Hs = 3.5 m and
Tp = 6 s. At full scale the 30° configuration produced the equivalent of 269.2 kW in
conditions of Hs = 4.5 m and Tp = 8 s. These values show the device successfully
captures and generates power and is suitable for further development.
The findings presented in this thesis have increased understanding of behaviour of
the WaveCat in a wide range of wave conditions and across two wedge angles.
Date of Award | 2022 |
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Original language | English |
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Awarding Institution | |
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Supervisor | Jon Miles (Other Supervisor) |
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- Wave energy
- Overtopping
- Wave field interaction
- Wavecat
WaveCat Wave Energy Converter: Performance and Wave Field Interaction
Allen, J. (Author). 2022
Student thesis: PhD