Author(s): V. Krivtsov; B. Linfoot
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Keywords: No Keywords
Abstract: This paper describes the physical model testing of an array of wave energy devices undertaken in the NTNU Trondheim basin during 8th to 20th October 2008 funded under the EU Hydralabs III initiative, and provides a preliminary analysis of the extreme mooring loads. Tests were completed at 1/20 scale on a single oscillating water column device and on close-packed arrays of three and five devices following calibration of instrumentation and the wave and current test environment. One WEC was fully instrumented with mooring line load cells, optical motion tracker and accelerometers and tested in regular waves, short-and long-crested irregular waves and current. The wave and current test regimes were measured by six wave probes and a current meter. Arrays of three and five similar WECs, with identical mooring systems, were tested under similar environmental loading with partial monitoring of mooring forces and motions. Preliminary analysis of the data indicate that close–packed arrays of energy converters may be more efficient in energy capture that the same number of similar devices. The majority of loads on the mooring lines appeared to be broadly consistent with both logistic and normal distribution, whilst the right tail appeared to confirm to the extreme value distribution. Comparison of the loads at different configurations of WEC arrays suggests that the results are broadly consistent with the hypothesis that the mooring loads should differ. In particular, the results from the tests in short crested seas conditions give an indication that peak loads in a multi WEC array may be considerably higher than in 1-WEC configuration. The test campaign has contributed essential data to the development of Simulink and Orcaflex models of devices which include mooring system interactions and data has also been obtained for inter-tank comparisons, studies of scale effects and validation of mooring system numerical models. Testing of arrays of WEC in Strangford Lough, Northern Ireland is planned to begin in Summer 2010.
Year: 2010