Long-term statistics of nonlinear wave crests via the equivalent power storm model

This paper is concerned with the estimation of the return period of nonlinear wave crests at a given location. The problem is of interest in several marine applications, as it is connected to the determination of the wave loads associated to severe sea storms. The paper disseminates the Equivalent Power Storm (EPS) based methodology for representing sequences of sea storms by fictitious storms with a prescribed time history. It is shown that such a method is capable of providing closed form solutions to the return values of nonlinear crest heights. Further, it allows determining the probability that a certain (nonlinear) crest height occurs during the lifetime of the structure. The method is applied via buoy data gathered at different water depth. Moreover, the paper proposes a method for obtaining the crest height statistics in shallow water from deep water data.