37 research outputs found
Influence of foundation model complexity on the design loads for offshore WTG on jacket foundation
Application of the Aero-Hydro-Elastic Model, HAWC2-WAMIT, to Offshore Data from Floating Power Plants Hybrid Wind- and Wave-Energy Test Platform, P37
Experimental and Theoretical Analysis of a Combined Floating Wave and Wind Energy Conversion Platform
IEA Annex 30 Offshore Code Collaboration Continued (OC4) phase I+II. Final report of the contributions from EUDP 64010-0071
OC5 Project Phase II: Validation of Global Loads of the DeepCwind Floating Semisubmersible Wind Turbine
This paper summarizes the findings from Phase II of the Offshore Code Comparison,
Collaboration, Continued, with Correlation project. The project is run under the
International Energy Agency Wind Research Task 30, and is focused on validating the
tools used for modeling offshore wind systems through the comparison of simulated
responses of select system designs to physical test data. Validation activities such as
these lead to improvement of offshore wind modeling tools, which will enable the
development of more innovative and cost-effective offshore wind designs. For Phase II
of the project, numerical models of the DeepCwind floating semisubmersible wind
system were validated using measurement data from a 1/50th-scale validation campaign
performed at the Maritime Research Institute Netherlands offshore wave basin.
Validation of the models was performed by comparing the calculated ultimate and
fatigue loads for eight different wave-only and combined wind/wave test cases against
the measured data, after calibration was performed using free-decay, wind-only, and
wave-only tests. The results show a decent estimation of both the ultimate and fatigue
loads for the simulated results, but with a fairly consistent underestimation in the tower
and upwind mooring line loads that can be attributed to an underestimation of waveexcitation
forces outside the linear wave-excitation region, and the presence of
broadband frequency excitation in the experimental measurements from wind.
Participant results showed varied agreement with the experimental measurements
based on the modeling approach used. Modeling attributes that enabled better
agreement included: the use of a dynamic mooring model; wave stretching, or some
other hydrodynamic modeling approach that excites frequencies outside the linear wave
region; nonlinear wave kinematics models; and unsteady aerodynamics models. Also, it
was observed that a Morison-only hydrodynamic modeling approach could create
excessive pitch excitation and resulting tower loads in some frequency bands.This work was supported by the U.S. Department of Energy under Contract No. DEAC36-
08GO28308 with the National Renewable Energy Laboratory. Some of the
funding for the work was provided by the DOE Office of Energy Efficiency and
Renewable Energy, Wind and Water Power Technologies Office