Modeling FOWT hydrodynamic behavior with comparison to basin test experiments

The offshore wind industry is following a fast increase in Europe, leading developers to consider sites with higher water depths and to move to floating foundations. Floating Offshore Wind Turbines (FOWT) are complex systems whom design requires multi-physic models: aerodynamics, structural dynamics, hydrodynamics. The present paper investigates the validation of 2 FOWT numerical models against a set of experimental results provided by the University of Plymouth, within the ISOPE 2023 FOWT comparative study. The first numerical model, DIEGO, is an aero-hydro-servo-elastic solver similar to engineering tools used by the industry for the FOWT structural design.It can be seen a “low-fidelity” model, as it relies on simplified hydrodynamic assumptions (linear potential flow, Morison drag). The second numerical model, neptune_cfd, is a multi-phase Navier-Stokes solver able to handle wave-body interactions using a discrete forcing method to represent the structure on a cartesian mesh. It can be seen as a “high-fidelity” model of the FOWT in waves. The results presented show a good agreement between the 2 numerical models and the experimental references.