A Generic Method to Model Frequency-Direction Wave Spectra for FPSO Motions

We report a new approach to model the frequency-direction spectrum, in which the frequency-direction spectra from measurements or hindcast studies are fitted simultaneously in two dimensions, frequency and direction. Depending on the amount of wind forcing on the partition, either a unimodal (swell) or bimodal (wind-sea) wave spreading function is adopted together with the spectral form which best fits the frequency spectrum. This paper describes the new method and presents the results on a measured dataset.