Towards a Statistical Validation of the Critical Wave Groups Method for Free-Running Vessels in Beam Seas

Abstract

Research on the statistics of extreme events using deterministic wave group methods has largely been simplified to vessels at zero or constant speed and heading. In contrast, free-running vessels move with six degrees-of-freedom (6-DoF), leading to more complex and varied extreme response events. This paper details the extension of the Critical Wave Groups (CWG) method to free-running vessels and demonstrates that the method produces probability calculations comparable to those from a limited Monte Carlo dataset for a vessel in beam seas. This research is a critical first step in the formal validation of this free-running implementation of the CWG method.

Figures (11)

• Figure 1: Identification of a critical wave group for a given set of wave groups with similar shapes.
• Figure 2: Markov chain construction of wave groups and additional geometric constraints (figure adapted from Anastopoulos2016).
• Figure 3: Ensemble of wave groups with the same $T_c$, $j$, and $H_c$ = 5$\sigma$, 6$\sigma$, 7$\sigma$, 8$\sigma$, and 9$\sigma$.
• Figure 4: Representation of deterministic wave group at origin with Fourier components.
• Figure 5: Encountered wave elevation traveling through the repeating wave group wave field with constant speed and heading.