|dc.description.abstract||Floating wind technology has the potential to produce low-carbon electricity on a large
scale: it allows the expansion of o shore wind harvesting to deep water, indicatively
from 50-60 to a few hundred metres depth, where most of the worldwide technical
resource is found. New design specifi cations are being developed for
floating wind in
order to meet diverse criteria such as conversion effi ciency, maintainability, buoyancy
stability, and structural reliability. The last is the focus of this work.
The mechanics of
floating wind turbines in wind and waves are investigated with an
array of numerical means. They demand the simulation of multiple processes such
as aerodynamics, hydrodynamics, rotor and structural dynamics; understanding their
interaction is essential for engineering design, verifi cation, and concept evaluation. The
project is organised in three main parts, presented below.
Aero-hydro-mechanical simulation, characterising the rigid-body motions of a
wind turbine. An investigation of multi-physical couplings is carried out, mainly
through EDF R&D's time-domain simulator CALHYPSO. Wave forces are represented
with the potential-
ow panel method and the Morison equation. Aerodynamic forces
are represented by a thrust model or with the blade element momentum theory.
Main fi ndings: Exposure of fi nite-angle coupling for semi-submersible turbines with
focus on heave plate excursion; characterisation of the aerodynamic damping of pitch
motion provided by an operating vertical-axis turbine.
Dynamic mooring simulation, focussed on highly compliant mooring systems, where
fluid-structure interaction and mechanical inertial forces can govern line tension.
EDF R&D's general-purpose, finite-element solver Code Aster is confi gured for this use
exploiting its nonlinear large-displacement and contact mechanics functionalities.
Main findings: Demonstration of a Code Aster-based work
ow for the analysis of catenary
mooring systems; explanation of the dynamic mooring eff ects previously observed
in the DeepCwind basin test campaign.
Aeroelastic analysis of vertical-axis rotors, aimed at verifying novel large-scale
wind turbine concepts in operation, when aeroelastic-rotordynamic instabilities
may occur. The finite-element modal approach is used to qualify rotor vibrations and
to estimate the associated damping, based on the spinning beam formulation and a
linearised aerodynamic operator.
Main fi ndings: Characterisation of the vibration modes of two novel vertical-axis rotor
concepts using the Campbell diagram; estimation of the related aerodynamic damping,
providing information on the aeroelastic stability of these designs.||en