Statistical properties of mechanically simulated random wave fields were studied. Possible dependence of wave height and surface elevation distributions on the broadness of the spectral shape were analyzed by varying the parameters of the JONSWAP spectrum. Present results indicate that wave heights in the flume can be better approximated by the theoretically based Rayleigh. However, X2 goodness-of-fit test results indicate that both the Gaussian and the Weibull distribution can also be used as well.
Under the assumption that a wave field is composed of linear, independent waves each having their own frequencies and speeds, wave spectrum can be used to characterize all the possible constituents in that field. Wind waves are, however, known to be nonlinear, and nonlinearity leads to distortions of the linear results; so that other characteristics become important. Myhaug and Kjeldsen (1984), for example, has proposed to use parameters "such as "crest front steepness" and "vertical asymmetry factor" for characterizing the sea surface roughness. Distributions of wave heights and surface" elevations are other important features of a rough sea. Wave height distributions have been studied by many researchers, with the main conclusion that, in general, the theoretically based Rayleigh distribution fits measured results well, although it overpredicts larger wave heights (Chakrabarti and Cooley, 1977). As alternative, the two-parameter Weibull distribution was proposed (Forristall, 1978), good agreements between measured and predicted results were reported (Mase, 1989). Quite recently, Yim et al. (1995) analyzed laboratory results, and found that, wave heights can be better approximated either by a Gaussian or a two-parameter Weibull distribution, both have smaller X2 values when compared with that of Rayleigh. Disturbed by turbulent wind action, and subjected to the influences of meteorological, as well as topological, effects, wave characteristics of a specific location are to be best studied based upon measured results.
