Performance Analysis of a 3D Axisymmetric Oscillating Water Column

This paper presents an analysis, by numerical simulation, of the effects of some geometric parameters on the efficiency of an axisymmetric oscillating water column wave energy converter by using ANSYS ICEM CFD and CFX. The study is focused, principally, on the variation of power take off size, front wall shape, air column size, wave conditions and the chamber upper surface shape. A Stokes 2nd order wave is generated in a numerical wave tank in which the propagation is predicted by the use of the Reynolds averaged Navier Stockes (RANS) equations, k-ɛ turbulence model and the two-phase homogeneous volume of fluid (VOF) model. The power take off is modeled by an orifice and the flow parameters, air pressure and velocity, are calculated at its center. Simulation results shows that the orifice diameter, the front wall orientation vs. flow direction and the air column size affect, in a remarkable manner, the device performance, whereas the number of orifices has no physical impact.