Non-Gaussian Statistics of Mechanically Generated Unidirectional Irregular Waves

Abstract An experimental study is presented on the non-Gaussian statistics of random unidirectional laboratory wave fields described by JONSWAP spectra. Relationships between statistical parameters indicative occurrence large-amplitude waves are discussed in context initial steepness combined with effect spectral peakedness. The spatial evolution relevant and features also considered. It demonstrated that over distance spectra exhibit typical for developing nonlinear instabilities, such as broadening downshift peak, along lowering high-frequency tail decrease peak magnitude. clearly show an increase third-order nonlinearity distance, which can be significant, depending input environment. steeper conditions, however, while favouring extremely large waves, chances breaking loss energy due to dissipation, results lower extreme crests heights. applied Miche-Stokes-type criteria do confirm some extremes exceed limiting individual steepness. Eventually, this result agrees observation largest number abnormal recorded sea states moderate