Aeroelastic Modeling of Large Off-shore Vertical-axis Wind Turbines: Development of the Offshore Wind Energy Simulation Toolkit

The availability of offshore wind resources in coastal regions makes offshore wind energy an attractive opportunity. There are, however, significant challenges in realizing offshore wind energy with an acceptable cost of energy due to increased infrastructure, logistics, and operations and maintenance costs. Vertical-axis wind turbines (VAWTs) are potentially ideal candidates for offshore applications, with many apparent advantages over the horizontal-axis wind turbine configuration in the offshore arena. VAWTs, however, will need to undergo much development in the coming years. Thus, the Offshore Wind ENergy Simulation (OWENS) toolkit is being developed as a design tool for assessing innovative floating VAWT configurations. This paper presents an overview of the OWENS toolkit and provides an update on the development of the tool. Verification and validation exercises are discussed, and comparisons to experimental data for the Sandia National Laboratories 34meter VAWT test bed are presented. A discussion and demonstration of a “loose” coupling approach to external loading modules, which allows a greater degree of modularity, is given. Results for a realistic VAWT structure on a floating platform under aerodynamic loads are shown and coupling between platform and turbine motions is demonstrated. Finally, future plans for development and use of the OWENS toolkit are discussed.