Aero-hydro-servo-elastic coupling of a multi-body finite-element solver and a multi-fidelity vortex method

Abstract

The manuscript presents a novel aero-hydro-servo-elastic coupling framework, MIRAS-HAWC2. In this coupling, the wind turbine blades and rotor-wake aerodynamics are modeled using a modified lifting-line theory which accounts for blade curvature, combined with a hybrid vortex method. The wind turbine structure and foundation are modeled using a finite-element and multi-body system approach. Last, hydrodynamics are modeled using Airy wave theory together with Morison's equation. An initial assessment of the performance of the aeroelastic coupling framework has been performed for steady rotor-only cases, assuming laminar inflow without shear. This included a comparison against fully resolved computational fluid dynamics, for both stiff and flexible blades showing an excellent agreement. In a second stage, the aero-hydro-servo-elastic coupling is used, comparing MIRAS-HAWC2 as well as blade-element momentum-based simulations with selected results from the Offshore Code Comparison Collaboration projects (OC3 and OC4), which study the NREL 5 MW turbine mounted on different offshore support structures. A good agreement has been obtained for the simulations of a monopile with rigid foundation, a tripod, and jacket support structures.