The aim of this thesis was to develop the theoretical and computational basis for a time-domain slendership theory based on the method of matched asymptotic expansions. The literature review traces the development and application of seakeeping theory to ships of realistic form, with particular interest in problems and applications pertinent to (relatively) small ships in large waves. It notes the development from linearized solutions, through various stages of introduction of non-linearity to 3D methods, culminating in time-domain modelling. It notes the trade-off between fidelity and economy in the application of various approximations, and notes the imperatives for rapid simulation of realistic ship-motions. The review considers the evolution of slender-ship theory and the potential for a body-exact slender-ship theory to meet the noted requirements. This work aims to support the objective of Sclavounos et al. (2013) in seeking “simple and robust analytical expressions for the sectional force distributions in wavelengths which are large relative to the vessel transverse dimensions yet comparable to ship length”. It therefore combines the following elements: development of a new formulation for the time-domain determination of body-exact forces on a slender-body in large waves; development of a numerical implementation of the new formulation; verification and validation of the new numerical tool for vertical motions at zero speed; and application of the new tool to analyse the relative importance of body-exact hydrodynamic forces versus FroudeKrylov and hydrostatic forces. The specific new contribution of this research consists in developing a time-domain solution of the body-exact, slender-ship, wave-body problem under the weak scatterer hypothesis; that is, with a nonlinear free surface condition linearized about the incident wave profile. The approach taken applied the method of matched asymptotic expansions to match a two-dimensional near field (inner) representation of flow with the three-dimensional far field (outer) representation in order to solve for the equivalent axial singularity strength distribution and longitudinal interaction function. This provides the basis for the time-domain analysis of vertical plane (sectional) forces in large waves which includes longitudinal interaction effects beyond the limitations of strip theory.
Richard Weston Greenwood (Thu,) studied this question.