Wave Tank Model – as simulated by AQWA

Director of studies: Professor Deborah Greaves

Funded by: self-funded

Researcher: John W Phillips

The research includes the study of the mechanism of power capture from sea waves and the performance of the Floating Clam, patented by Francis Farley.

Francis favours the use of an air turbine generator, for reasons of simplicity and reliability. However the Clam is particularly suited to the use of a hydraulic power take-off system and in this regard the Reactive Hydraulic Modulator (RHM) being developed by MacTaggart Scott & Co appears particularly interesting.

Complementary research at the University of Plymouth is directed at measuring and characterising the wave climate at the Wave Hub test site in Cornwall. Data from this research will be used in assessing the energy capture performance of the Clam in order to provide a realistic appraisal of its potential in real seas.

The research programme has two aspects – theoretical and practical. The theoretical aspect relies on the use of the computation tools, WAMIT and AQWA for frequency domain modelling to predict energy capture performance, while possible control strategies will be studied in the time domain using a continuous system modelling tool such as MatLab/Simulink. Physical model testing in the wave tank will be used to confirm the validity of the theoretical predictions.

The ultimate aim is to estimate the cost of energy at a particular site. The costing will be based on informal estimates of hardware and assembly costs for, say, 100 units. Costs for capital equipment, installation, maintenance and de-commissioning will be obtained, so as to give a measure of the cost of energy generated.

To date, a literature review has been carried out together with preliminary testing. Parallel undergraduate projects have also provided useful data. WAMIT predictions show very promising levels of power capture and the current emphasis is building a wave tank model. The model power take off, involves the innovative use of a miniature hydraulic ram (a modified bicycle pump) plus a small pressure vessel and an associated sharp-edged orifice.​

Wave Tank Model – as simulated by AQWA

Wave Tank Model – as simulated by AQWA