Variability of Kinetic Response Estimates of Froude Scaled DeepCwind Semisubmersible Platforms Subjected to Wave Loading

Abstract

Froude scaling for Floating Offshore Wind Turbine (FOWT) platforms is typical for understanding and interpreting their behavior and subsequent designs for testing in wave basins. Despite its popularity, the variability and uncertainty of the kinetic responses of such floating structures as a function of scaling require more attention. This work addresses the question of consistency of Froude scaling by comparing the hydrodynamic responses of a range of DeepCwind semi-submersible FOWT scaled models (full model, ½, ¼, 1/9, 1/16, 1/25, 1/36, 1/49 and 1/50). The comparation was made both in the mooring line tension and bending moment of structural members, which are directly related to their safety limit states. Hydrodynamic forces due to diffraction, radiation and viscosity along with hydrostatic forces and mooring boundaries are modeled by Ansys Aqwa, which were subsequently converted to bending moment estimates. The variability of kinetic responses like mooring line tensions and bending moment estimates was investigated for each scaled model, along with identification of regions of inconsistencies. In the context of offshore renewable energy development through technological readiness levels, the study is especially pertinent for understanding how force variabilities and uncertainties are related to these kinetic responses of semisubmersible platforms.