NUMERICAL SIMULATION OF AN OSCILLATING WAVE SURGE CONVERTER

It has been known that bottom hinged Oscillating Wave Surge Converters (OWSCs) are an efficient way of extracting power from ocean waves (Whittaker et al. 2007). OWSCs are in general large buoyant flaps, hinged at the bottom of the ocean and oscillating back and forth under the action of incoming incident waves (Schmitt et al. 2012, Renzi and Dias 2012). The oscillating motion is then converted into energy by pumping high-pressure water to drive a hydro electric turbine. This paper deals with numerical studies of wave loading on an OWSC using the FLUENT software. In numerical simulation of wave loading on an OWSC using mesh-based methods, the mesh around the flap is required to be updated frequently. This is due to the large amplitude rotation of the OWSC around the hinge. In this work, the remeshing was achieved by using the so-called dynamic mesh approach built in FLUENT. Furthermore, the motion of the OWSC is updated in time using a fourth order multi point time integration scheme coupled with the flow solver. The results for the flap motion and the excited torque on the hinged position were compared with experimental data obtained in a wave tank at Queen's University of Belfast. The results showed the capability of the numerical model with a dynamic mesh approach in modeling large amplitude motions of the flap. In addition, the pressures at various locations on the flap were compared with the experimental measurements in order to demonstrate the accuracy of the proposed model in capturing local features of the flow as well as the global features.