A NEW MODEL FOR LONG-TERM STOCHASTIC-ANALYSIS AND PREDICTION .1. THEORETICAL BACKGROUND

ATHANASSOULIS, GA; VRANAS, PB; SOUKISSIAN, TH

dc.contributor.author	ATHANASSOULIS, GA	en
dc.contributor.author	VRANAS, PB	en
dc.contributor.author	SOUKISSIAN, TH	en
dc.date.accessioned	2014-03-01T01:41:20Z
dc.date.available	2014-03-01T01:41:20Z
dc.date.issued	1992	en
dc.identifier.issn	0022-4502	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/23462
dc.subject.classification	Engineering, Marine	en
dc.subject.classification	Engineering, Civil	en
dc.title	A NEW MODEL FOR LONG-TERM STOCHASTIC-ANALYSIS AND PREDICTION .1. THEORETICAL BACKGROUND	en
heal.type	journalArticle	en
heal.language	English	en
heal.publicationDate	1992	en
heal.abstract	A new approach for calculating the long-term statistics of sea waves is proposed. A rational long-term stochastic model is introduced which recognizes that the wave climate at a given site in the ocean consists of a random succession of individual sea states, each sea state possessing its own duration and intensity. This model treats the sea-surface elevation as a random function of a "fast" time variable, and the time history of the spectral characteristics of the successive sea states as a random function of a "slow" time variable. By developing an appropriate conceptual framework, it becomes possible to express various probabilistic characteristics of the sea-surface elevation, which are sensible only in the fast-time scale, in terms of the statistics of sea-states duration and intensity, which is meaningful only in the slow-time scale. As an example, we study the random quantity M(u)(T) = "number of maxima of the sea-surface elevation lying above the level u and occurring during a long-term time period [0,T]." Exploiting the proposed framework, it is shown that, under certain clearly defined assumptions, M(u)(T) can be given the structure of a renewal-reward (cumulative) process, whose interarrival times correspond to the duration of successive sea states. Thus, using renewal theory, the complete characterization of the probability structure of M(u)(T) is obtained. As a consequence, the long-term probability distribution function of the individual wave height is rigorously defined and calculated. The relation of the present results with corresponding ones previously obtained is thoroughly discussed. The proposed model can be extended twofold: either by replacing some of the simplifying assumptions by more realistic ones, or by extending the model for treating the corresponding problems for ship and structures responses.	en
heal.publisher	SOC NAVAL ARCH MARINE ENG	en
heal.journalName	JOURNAL OF SHIP RESEARCH	en
dc.identifier.isi	ISI:A1992HR19400001	en
dc.identifier.volume	36	en
dc.identifier.issue	1	en
dc.identifier.spage	1	en
dc.identifier.epage	16	en