Full Resolution of Extreme Ship Response Statistics

TL;DR

This paper introduces an efficient framework combining nonlinear wave simulation and CFD to accurately compute extreme ship response statistics in irregular wave fields, reducing computational costs compared to full Monte-Carlo methods.

Contribution

It develops a novel, integrated approach that efficiently estimates extreme ship motions considering wave nonlinearity, applicable to realistic ship response scenarios.

Findings

Wave nonlinearity significantly affects extreme response statistics.

The framework accurately predicts extreme ship motions with reduced computational effort.

Coupling with CFD demonstrates applicability to real-world ship motion problems.

Abstract

We consider the statistics of extreme ship motions in a nonlinear irregular wave field. While an accurate computation is possible by using a full Monte-Carlo method to cover all individual wave conditions, the computational cost may become prohibitively high (when coupled with high-fidelity simulations) due to the rareness of the extreme events. In this work, following existing methods of sequential sampling and wave group parameterization, we implement a framework incorporating nonlinear wave simulation and ship response CFD simulation, which allows the extreme ship motion statistics in nonlinear wave field to be computed efficiently. We test the validity of the framework for the cases of ship response calculated by a nonlinear roll equation, and show the importance of wave nonlinearity to the extreme response statistics. Finally, the framework is coupled with the CFD model to demonstrate its applicability to more realistic and general ship motion problems.