Chapter 3 - Random Wind-Generated Waves: Basic Concepts

Abstract

The chapter starts with some basic concepts: sea state, significant wave height, spectrum, sea state=stationary Gaussian random process, with the linear theory; some basic relationships including that between autocovariance and spectrum; and the useful concept of “very narrow spectrum.” Then it passes to the characteristic spectra of wind seas (JONSWAP, TMA), and the relationship between peak period and significant wave height with the JONSWAP spectrum. The crucial problem of obtaining the continuous spectrum from time series data is introduced in a fresh way consisting in a sort of play. This may be played by two persons or two teams of students, as it is shown in a worked example. The chapter concludes with the introduction of the concept of small-scale field experiment, which together with the quasi-determinism theory form the backbone of this book.