Hydrodynamic Coefficient Computation for a Partially Submerged Wave Energy Converter

This paper deals with the hydrodynamic parameter computation of a wave energy converter (WEC) that consists of a cylindrical buoy sliding along a partially submerged platform made up of a plate and a column. The computed parameters are especially needed for the development of a simple hydrodynamic time-dependant model, based on the Cummins´ formulation. This model is intended for WEC control purposes. A semi-analytical approach is proposed for the computation of the hydrodynamic coefficients and the excitation forces. The boundary value problem is solved by using variable separation and matched eigenfunction expansion methods. Analytical expressions for the velocity potential are then obtained for each subdomain. The hydrodynamic coefficients and the excitation force can then be computed by using these expressions. Numerical results are given for different buoy, column, and plate radii and clearly the bearing surface of the plate has a significant influence on the wave excitation force applied to the submerged platform.