DESCRIPTION OF NATURAL SEA STATES: REQUIREMENTS TO THE REPRODUCTION IN MODELS

H. Lundgren, Elias Davidsen

Abstract


In order to attain a satisfactory reproduction in physical and numerical models of Nature's sea states, much development of the description of these sea states has to take place. This paper gives a discussion (i) of the problems that can be considered as solved today, and (ii) of the problem areas where much research is still needed. Firstly, the paper presents the basic definition of the directional spread of energy (for a given frequency) as derived from a field record. This definition is necessarily a statistical one and leads directly to the determination in practice of the directional spectrum. Secondly, the parameterization of spectra is discussed and it is proposed to express one-dimensional storm spectra by means of the four -parameter F.1 .-spectrum, which is more manageable than the JONSWAP-spectrum. Thirdly, it is concluded that the first order components of any spectrum have random phases.

Keywords


model reproduction; sea state; sea state description

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