Nonlinear Effects of Wave Heights on Coupled Sloshing and Seakeeping Responses

Abstract

With increased activities in natural gas transportation and offshore exploration in the past decades, assessment of sloshing in liquefied natural gas (LNG) tanks has become an important practical issue. In this paper, we focus on the deterministic calculation of the coupled sloshing and ship motions in regular wave conditions. An in-house numerical code is used to solve the seakeeping problem coupled with the sloshing dynamics. The numerical method adopts a weakly nonlinear approach using impulse response functions for the seakeeping problem. Nonlinear Froude-Krylov and hydrostatic forces are directly evaluated in the time domain. A three-dimensional finite difference method is applied to solve the sloshing problem. The numerical method is validated by comparing with experimental results in the literature. The developed numerical method is used to analyze the nonlinear effects of wave heights.