CFD simulations of a passively controlled point absorber

Time 
01/25/2017 - 15:00-01/25/2017 - 16:30
Room 
Sasakawa Auditorium

Authors

Minghao Wu
(Department of Shipping and Marine Technology, Chalmers University of Technology)
Weizhi Wang
(Department of Shipping and Marine Technology, Chalmers University of Technology)
Johannes Palm
(Department of Shipping and Marine Technology, Chalmers University of Technology)
Claes Eskilsson
(Department of Shipping and Marine Technology, Chalmers University of Technology)

Theme

Speaker(s): 
Minghao Wu Weizhi Wang

Recently CorPower Ocean presented laboratory tests of a point absorber wave energy converter equipped with a novel technique for passive phase control (Hals Todalshaug et al, 2015). The technique, known as WaveSpring, widens the response bandwidth by a negative spring arrangement, and in the tank experiment an up to three-fold increase in delivered power as compared to pure linear damping was observed. As previously reported, for point absorbers close to resonance the use of standard radiation-diffraction models can become unreliable while CFD simulations accurately captures the nonlinear wave height dependent response (Yu and Li, 2015; Palm et al, 2016). Thus, in the present study a module representing the Wave Spring technology was implanted in the OpenFOAM framework and CFD simulations of the buoy were performed both with and without the Wave Spring module. Good agreement between simulated and experimental results was observed, and the WaveSpring behavior was well captured in the numerical simulation. The CFD model can be used for further tuning of the WaveSpring/bouy design as well as providing validation data for radiation-diffraction models.