A comparison between different numerical models and experimental tests for the study of floating offshore wind turbines

The content of the present paper is the comparison between three different numerical models with the results of the experimental campaign conducted by the University of Plymouth, in the context of the 1st FOWT Comparative Study. Experimental tests were conducted to evaluate the hydrodynamic properties of a 1:70 scaled Volturn US semisubmersible floating platform, supporting a 15 MW offshore reference wind turbine coupled with the mooring system. This paper uses three different software with increasing numerical accuracy: MOST, Orcaflex, and STARCCM+. MOST is a numerical model developed by the Politecnico di Torino and implemented in a Matlab-Simscape environment; Orcaflex is a commercial software dedicated to offshore structure analysis, especially used for the design of mooring systems; STAR-CCM+ is commercial software for CFD analysis based on Unsteady Reynolds-Averaged Navier-Stokes equations (URANS). The tests considered for the validation of the experimental tests include free decay tests and focused wave tests. All the experiments are performed considering the 1:70 scaled Volturn US semisubmersible floating platform in its moored configuration. The results show how linear models, if properly calibrated, can provide more than satisfactory results with a low computational cost.