Master forsvar Ioannis Bertsios

Supervisorer: Antonio Pegalajar-Jurado, Freddy Johannes Madsen and Henrik Bredmose

Censor: Bjarne Skovmose Kallesøe, Siemens-Gamesa Renewable Energies

Numerical study of DTU 10MW floating offshore wind turbine (FOWT) on TetraSpar platform using HAWC2 software

A numerical model of a 1:60 scaled floating wind turbine was examined in terms of agreement with experiments. The wind turbine was the DTU 10MW RWT and it was mounted on the spar configuration of the TetraSpar floater.

Firstly, the wind field was calibrated in order to determine the mean wind speed experienced in hub height as well as the turbulence intensity according to the experiments. Afterwards, the
damping level in the model was investigated and further calibration was done in order to replicate the basin tests. A trial and error method was applied by changing the
hydrodynamic damping in HAWC2.

The numerical model was simulated for wind-only, waves-only (regular, irregular and focused) as well as the combination of wind and waves. The calibration focused on the cases of irregular
waves, with and without wind, which are more representative for a real environmental condition. Moreover, misaligned cases with a wave heading of 30_ were tested and further calibrated when
wind loads were present. The comparisons between model and test were illustrated with time series, power spectral density and probability exceedance plots.

Although, the first approach was simulated without second-order hydrodynamics, these forces were included by using the Newman approximation and both the calibration and the presented
results are related to the latter. Some comparisons between the motion responses with and without second-order loading are described.

The numerical model seemed to underpredict the in-plane motions and this phenomenon was amplified for smaller sea states. Furthermore, the behavior in rated wind speed may indicate
uncertainties in wind speed inputs or controller tuning, indicating the importance of further research on these issues. The followed procedure of damping calibration was able to provide a
good match between high-fidelity aeroelastic code HAWC2 and the derived data from the test campaign, opening up new areas of research and pointing out crucial improvements and checks
for further investigation of either related numerical studies or the existed one.


man 23 sep 19
13:00 - 15:00


DTU Vindenergi


DTU Lyngby Campus, Nils Koppels Alle, Bygning 403, lokale 219, 2800 Lyngby