Generation and Analysis of 2-Dimensional IrreguLar Water Waves

Abstract

In order to simulate irregular waves with directional spectrum in a model basin, the authors studied the characteristics of directional waves generated in a model basin numerically and experimentally, They found out that the power spectrum of directional waves which consist of component waves with same frequencies as ones of one another direction is non-stationary-in-position. They proposed to use stationary-in-position directional waves in a model basin which consist of component waves with different frequencies from ones of one another direction. They also discussed three methods of analysing directional spectrum, those are, Maximum Liklihood Method (M.L.M.), Direct Integral Method (D.I.M.) and Fourier Series Expansion Method (F.S.E.M.). By using of these three methods, They derived numericaly directional spectrum from cross spectrum calculated directly from designed directional spectrum and they also derived directional spectrum from numerical time-histories of irregular waves with designed dierectional spectrum. They concluded that M.L.M. is on of the best analytical methods but it is not alway the best in any case.