Advanced Structures & Composites Center

Paper by Viselli, Goupee, Dagher, and Allen Published in Wind Energy

A paper titled, “Design and Model Confirmation of the Intermediate Scale VolturnUS Floating Wind Turbine Subjected to its Extreme Design Conditions Offshore Maine,” has been published in Wind Energy September 2015. The paper was authored by Dr. Anthony M. Viselli,  Dr. Andrew J. Goupee, Dr. Habib Dagher, and Christopher K. Allen.

“Floating offshore wind turbines are gaining considerable interest in the renewable energy sector. Design standards for floating offshore wind turbines such as the American Bureau of Shipping (ABS) Guide for Building and Classing Floating Offshore Wind Turbine Installations are relatively new and few if any floating wind turbines have yet experienced the prescribed design extreme environmental conditions. Only a few pilot floating turbines have been deployed in Europe and Japan. These turbines have been designed for long return period storm events and are not likely to see their extreme design conditions during early deployment periods because of the low probability of occurrence. This paper presents data collected for an intermediate scale floating semi-submersible turbine intentionally placed offshore Maine in a carefully selected site that subjects the prototype to scale extreme conditions on a frequent basis. This prototype, called VolturnUS 1:8, was the first grid-connected offshore wind turbine in the Americas, and is a 1:8 scale model of a 6 MW prototype. The test site produces with a high probability 1:8 scale wave environments, and a commercial turbine has been selected so that the wind environment/rotor combination produces 1:8-scale aerodynamic loads appropriate for the site wave environment. In the winter of 2013–2014, this prototype has seen the equivalent of 50 year to 500 year return period storms exercising it to the limits prescribed by design standards, offering a unique look at the behavior of a floating turbine subjected to extreme design conditions. Performance data are provided and compared to full-scale predicted values from numerical models. There are two objectives in presenting this data and associated analysis: (i) validate numerical aeroelastic hydrodynamic coupled models and (ii) investigate the performance of a near full-scale floating wind turbine in a real offshore environment that closely matches the prescribed design conditions from the ABS Guide.”