CFD study of extreme ship responses using a designed wave trail

Abstract

The need for fully physics-based nonlinear solvers such as URANS CFD solvers is imminent to evaluate extreme ship responses in a seaway. However, such computations are very time-consuming and practically impossible to search through all wave environments to evaluate the extreme ship responses and ship survivability, which are considered rare but influential events. One way to enhance the practicality of the nonlinear tools is to develop physics-informed mathematical methods, in which the wave trail can be designed statistically by the information provided by the limited number of nonlinear simulations. In this study, the extreme responses of KRISO Container Ship (KCS) are analyzed using wave trails designed by the conditioning technique based on one irregular wave simulation. An irregular wave simulation was conducted for the ship advancing at Fr = 0.26 in waves with JONSWAP spectra under Seas State 5. Three wave trails are designed to generate heave responses with a maximum amplitude of 0.08, 0.16, and 0.2 m (28%, 56%, and 70% of the ship draft) using Gaussian and non – Gaussian processes. CFD simulations with the designed wave trails revealed that the designed wave trails often result in the desired heave response. Additional simulations are also performed in calm water and regular waves for verification and validation purposes.