Analyzing the impact of aeroelastic model fidelity on control co-design optimization of floating offshore wind turbines

Abstract. This work investigates the influence of aeroelastic modeling fidelity on design optimization of floating offshore wind turbines. To this end, the QBlade simulation environment was coupled to the Wind Energy with Integrated Servo-control wind turbine design and optimization framework. QBlade offers aerodynamic and structural models with varying levels of aeroelastic fidelity within a computationally efficient implementation. This enables time-domain optimization studies with levels of aeroelastic fidelity that are currently often deemed unfeasible for such purposes due to the computational expense involved. Five fidelity combinations are considered, ranging from blade element momentum aerodynamics with torsion-constrained Euler–Bernoulli beams to lifting-line free vortex wake aerodynamics with fully populated Timoshenko beams. To assess how aerodynamic and structural modeling fidelity influences optimization outcomes, the parameters of the floating wind turbine controller are co-designed together with the floating substructure, a system typically considered less sensitive to aeroelastic fidelity. The results show that final design outcomes are affected by the chosen fidelity level. In this case study, higher-fidelity models modified and broadened the feasible design space and thereby led to improved design outcomes, albeit at the expense of higher computational cost.