Second order drift forces on "Offshore" Wave Energy Converters

Objective of this contribution is to present a procedure for evaluating second order drift forces on floating bodies, often the most important loading component for mooring design, in case of high waves propagating in relatively shallow water depths. The non linearity associated to this condition, which is typical of installations involving wave energy converters, makes this problem particularly interesting. In particular, the note focuses on the a second order force term that depends on the second order potential. Peculiarity of the method is a simple way to compute the product of two phasor variables. It is shown in great details how to carry out the computation by means of Comsol Multiphysics.