WEIBULL DISTRIBUTION BASED DESIGN WAVE HEIGHTS

摘要

In practice, the wave height distribution associated with an irregular wave train is always mathematically modeled as a Rayleigh distribution. However, the present study demonstrates that a better mathematical model for wave height distribution under realistic ocean environment is a Weibull distribution. In comparison with a Rayleigh distribution, a Weibull distribution has the flexibility on choosing its "shape parameter." One of the objectives in this study is to analytically derive general relationships among various representative wave heights based on the assumption of a Weibull wave height distribution. According to Monte Carlo simulations and field data, this study finds that the ratio of the significant wave height and root-mean-square wave height is always near to 1.4, insensitive to the shape of wave spectrum. In turn, the wave height distribution is the particular Weibull distribution with its shape parameter near to 2.13. This feature is largely attributed to the fact that the wave height identification is via a "zero-crossing" technique where high frequency components have minor influence on wave height distribution.