Three-Dimensional Effects for a Ship Experiencing Large Amplitude Roll Motion

Abstract

Recent advancements have been made to consider the effects of large amplitude motions for roll damping models used for numerical ship motion performance assessments. These advancements have been focused on the development and expansion of models for potential flow simulation tools with sectional formulations. However, additional 3D effects due to vortex shedding, flow convection downstream, waves, and bilge keel emergence and submergence during large roll motion may be important, but are typically neglected in the sectional formulations. A series of RANS computations were performed for both 2D and 3D conditions of large amplitude ship roll motion, with and without forward speed, and in calm water and in waves. Comparisons were made to available experimental data for the 2D calm water conditions at zero-speed. These results were then assessed with the 3D conditions to develop improved understanding of additional 3D effects, including forward speed and waves, which should be considered for future developments of strip-theory approaches for ship motions prediction.