The motions and internal forces of a moored semi-submersible in regular waves

The motion of a moored semi-submersible in regular waves and the wave-induced internal forces in the semi-submersible have been studied both numerically and experimentally. In the numerical formulation, the semi-submersible is modelled as an externally constrained floating body, which is regarded as being composed of several rigidly connected parts. The linearized equations of motion of each part were obtained in a common reference system fixed on the body. A consistent formulation of the wave-induced internal forces between two parts as well as the external constraining forces is presented. Model tests were carried out using a 1:36 scale model of the semi-submersible, Glomar Arctic III. Very good agreement was achieved between the numerical and model-test results in the practical wave-frequency range.Peer reviewed: YesNRC publication: Ye