On the extreme statistics of long-crested deep water waves: theory and experiment

Quasi-resonant four-wave interactions may influence the statistical properties of deep water long-crested surface gravity waves. As a consequence, the wave height exceedance probability can substantially deviate from the expected distribution obtained by assuming that waves are linear. Here the occurrence probability of extreme events recently derived by N. Mori and P. Janssen (2006) is compared with wave tank data, where strong departures from Gaussian behavior are observed. Experimental wave height, maximum wave height distribution, and probability of occurrence of freak waves are compared with theoretical expectations. The theory well predicts extreme waves in nonlinear wavefields.