TRUNCATED MODEL TESTS FOR MOORING LINES OF A SEMI-SUBMERSIBLE PLATFORM AND ITS EQUIVALENT COMPENSATED METHOD

摘要

This study conducted a model test of 1:100 model scale of a semi-submersible platform with a 1500 m full-depth mooring system in the Joint Laboratory of Wind Tunnel & Wave Flume at Harbin Institute of Technology. A truncated mooring system of 400 m water depth was designed based on the static equivalent principle. The semi-submersible platform was tested under regular wave excitation periods that ranged from 10 s to 45 s and one year of irregular wave conditions in the South China Sea. The results validated the feasibility of using numerical simulation in the motions calculation of semi-submersible platform and showed that mooring damping may contribute significantly to the total damping of deepwater floating platform in the low frequency range. The viscous damper was designed to simulate the contribution of mooring damping and added to the numerical simulation of the motion calculation of semi-submersible platform with the truncated mooring line. The numerical simulation results were compared with the motion calculation of semi-submersible platform with the full-depth mooring line. This method can help solve the differences in the dynamics of truncated model tests that are typically used in ocean engineering.