Wave Height Distributions in Multiple-Peaked Seas

摘要

Knowledge of distributions of heights of sea waves under realistic oceanicconditions is critical to the successful design of coastal shore protection projects. In this report, a simple examination is made of wave height distributions in sea states characterized by energy spectra with multiple peaks, i.e., having energy centered at two or more distinct frequencies. Sea states with broad frequency spectra are also included since such seas are composed of waves of diverse frequencies. These cases violate the assumptions of unimodal, narrow spectra that are formally required for the conventionally used Rayleigh distribution of wave heights to apply. Reported here are tests of the Rayleigh and Modified Rayleigh wave height distribution models. These models are compared with wave heights from idealized, synthetic time series having spectra with variable widths, modes, and modal separations. The Modified Rayleigh model is the two-parameter, deepwater asymptotic form of the Beta-Rayleigh distribution.