Numerical modelling of multi-body hydrodynamics in multi-phase simulations

Abstract This thesis is concerned with the simulation of mechanically coupled bodies in a multi-phase environment. While the applictaions of such cases are very wide, they are of particular interest for offshore wind parks, where numerical investigations can support the safety margins of an operation. The computational focus of the the present study is to supplement a viscous three-phase fluid-soil solver featuring the overset-grid technique by appropriate mechanical models to analyse the hydrodynamics of complex systems composed of multiple mechanically coupled bodies. A quaternion-based motion modeller featuring several basic joint elements is used to model their influence in a multi-body arrangement or the mechanical interaction between different moving parts of a structure, which can be seen as a multi-body system. Implicit seaway boundary conditions allow the use of compact domain sizes and variable headings of incident waves. Validation examples includet refer to rigid links, ropes, fenders or guide frames restricting the motion in experiments, which aim to illustrate the predictive capabilities of the procedure. Finally, investigations on the simulation of a floating tug in waves, boatlanding for safe transfer, grounding of gravity foundations for wind turbines and the installation process of jack-up rigs in seaway involving structure-seabed interactions have been considered for application purposes while utilizing all features of the computational framework.