A newly developed maximum entropy method has been introduced to analysis the statistical characters of wave forces distribution in shallow water subject to random wave. The relationships between significant wave pressure and significant wave height are manifested. The results indicate that the well-designed maximum entropy distribution is consistent with the experimental data fairly well, superior to other widely used probability density functions.
As an important branch of water wave mechanics, how to determinate the forces induced by waves to fixed and compliant structures, as well as the motions of floating objects have attracted much attention in the past few decades (Dean and Dalrymple, 1998). As is well known, the objects, whether floating on the sea or attached to the bottom, are subject to wave forces more or less, therefore the attempt to predict the random wave forces accurately in the design of offshore structures become important and meaningful. Numerous studies have been done for wave forces imposed on vertical cylinders. Most research works focused on the interaction between fluid flow and cylindrical structures based on the Morison equation (such as Chaplin et al, 1993; Song, 2005, etc). According to the linear theorem of wind-generated waves (Longuet-Higgins, 1963; Philips, 1967), the linear Froude-Krylov force, whether on a vertical cylinder or on a horizontal submerged cylinder, can be expressed as a random Gaussian process in time domain. In fact, since the ocean wave process is essentially nonlinear (non-Gaussian), the omission of nonlinearity will distinctly reduce the accuracy of wave forces estimation. So far, the statistics approaches to wave forces analysis can be divided into two main aspects: the theoretical distribution based on the random wave model (Song et al, 2000, etc) and the statistical distribution. Yu et al.(1991) proposed that the peak value of wave force is fit for Weibull distribution in case of large c K numbers, and trends to Rayleigh distribution in case of small c K numbers, based on the analysis of the distribution of the instantaneous incline force of irregular wave.
