Efficiency of Trigonometric and Eigen Function Methods for Simulating Ocean Wave Profile

The series representation of ocean wave surface elevation profile using an existing spectral energy density can be achieved by linear superposition of terms in an expansion. This study demonstrates that the use of Karhunen-Loeve (K-L) expansion in which the eigenfunctions of Prolate Spheroidal Wave Functions (PSWFs) are used can be correlated with Fourier and constrained new wave approach in terms of computer cost required (3.225x103s, 3.0615x103s and 1.3221x104s respectively) in the wave simulation (maximum difference of 0.007% and minimum of 0.077%). It have also been demonstrated that the use of K-L with PSWFs can significantly reduce the number of the terms required to represent the wave which can greatly reduce the computational effort required in the statistical analysis of response from large offshore structures.