Analytic theory of a wind-driven sea

Abstract

A self-sustained analytic theory of a wind-driven sea is presented. It is shown that the wave field can be separated into two ensembles: the Hasselmann sea that consists of long waves with frequency omega < omega(H), omega(H) similar to 4- 5 omega(p) (omega(p) is the frequency of the spectral peak), and the Phillips sea with shorter waves. In the Hasselmann sea, which contains up to 95 % of wave energy, a resonant nonlinear interaction dominates over generation of wave energy by wind. White-cap dissipation in the Hasselmann sea in negligibly small. The resonant interaction forms a flux of energy into the Phillips sea, which plays a role of a universal sink of energy. This theory is supported by massive numerical experiments and explains the majority of pertinent experimental facts accumulated in physical oceanography. (C) 2018 The Authors. Published by Elsevier B.V.