Three-Dimensional Wave-Structure Interaction Modelling Using the Scaled Boundary Finite Element method

Abstract

In ocean engineering, the subject of wave-structure interaction has been the focus of heated debate for decades. Ocean engineers investigate wave behaviour in the presence of man-made structures, whilst structural engineers utilise accessible wave parameters to evaluate structural response. However, these two processes are closely related to each other, and difficulties exist if explicit wave forces are not available for structural analysis. Furthermore, differences in the theoretical background between wave and structural analyses pose additional challenges. Taking into consideration all these arguments, this PhD project aims to develop a three-dimensional wave-structure interaction model, assessing the wave field behaviour in the presence of structures, while simultaneously investigating subsequent structural response. The Scaled Boundary Finite Element Method (SBFEM) is adopted to formulate the interaction problem, having many advantages including: significantly releasing the computational burden of three-dimensional calculations; precisely satisfying the boundary condition at infinity; not requiring fundamental solutions and being free from irregular frequencies and singular integrals. This study is organised in order of increasing complexity of the physical problem and model formulation, from wave-monopile interaction through to wave interaction with pile group foundations, from steady scope examinations through to time-dependent investigations. In each case, waves and structures are formulated in a three-dimensional SBFEM model, which is subsequently used in well-designed parametric analyses, to derive a better understanding of the interaction mechanism.