Comparison of Numerical Simulation and Model Test for Integrated Installation of GBS Wind Turbine: Sammenligning av numerisk simulering og modellforsøk for installering av GBS vindturbin

Abstract

Reinertsen has developed a new installation concept for the transportation and installation of a fully assembled gravity based foundation offshore wind turbine (GBS-OWT) by means of a support double barge (DB) and standard tug boats. A numerical model of this design is built, based on experimental decay tests and irregular wave tests conducted in the scale 1:30.The generated numerical model includes hydrodynamic coupling, stiff wire and contact couplings, viscous elements and mean drift forces. Due to the complexity of this model and its strong coupling effects, a very challenging numerical problem in the field of marine operations is considered.Mooring line dynamics and viscous damping of the numerical model are determined by evaluating experimental decay tests. Numerical decay tests and irregular wave tests are conducted and the model responses are compared with those recorded in the experiments.Good accordance with the experimental responses is seen in the numerical decay tests. Numerical pitch and roll responses in irregular waves show good agreement as well. In addition, the mooring responses are significantly improved when mooring line dynamics are accounted for. However, further investigation into the mooring responses and the friction damping of relative DB-GBS heave responses is required to improve the numerical model.