Wave and current induced motions on TLPTAD multibody system

Abstract

This work presents an extensive experimental and numerical analysis with the aim of investigating wave and current induced motions of a tension leg platform – tender assisted drilling multibody system. The study includes an analysis of first and second-order wave loads on the system using the potential wave theory. It also analyzes the wave coupling effects by using frequency and time domain approaches. The analysis of current loads includes experimental tests to quantify shielding or interaction effects and numerical simulations using Computational Fluid Dynamics (CFD) to evaluate scale and blockage effects in the multi-body system considering several current velocities and angles of attack. Furthermore, this thesis includes an experimental study of vortex induced motions (VIM) and Galloping instabilities of the multi-body system when subject to currents. The motions developed by the TLP and the TAD in single-body cases are compared to multi-body cases when the floaters are disconnected and connected by a hawser system. Finally, with the aim of reducing the VIM response of the TLP, the work includes an analysis of several VIM mitigation devices investigating the influences of damping, natural frequencies, average current loads and the amplitude of the motions of the TLP.