In June, Brian Owens (in Sandia’s Analytical Structural Dynamics Dept.) and Todd Griffith (in Sandia’s Water Power Technologies Dept.) traveled to DTU Lyngby (Technical University of Denmark: Copenhagen, Denmark) to present Sandia research on deep-water multiple-megawatt vertical-axis wind turbines (VAWTs).

High tip-speed ratios, low frequency structural vibration modes, and flexible blades of multiple-megawatt VAWTs can give rise to aeroelastic stability concerns. Owens and Griffith presented on a design study of aeroelastic stability of very large VAWTs that used an enhanced version of the Offshore Wind Energy Simu­lation Toolkit for VAWTs.

Multiple-megawatt VAWT design concepts.

Multiple-megawatt VAWT design concepts.

While abroad, Griffith and Owens also attended a two-day VAWT workshop hosted by DTU Risø. The work­shop provided an opportunity to discuss current VAWT research and development status. Topics at the workshop included VAWT modeling, testing, and economics as well as VAWT design concepts and certifica­tion.

Retired Sandian Dale Berg also presented a historical perspective from the legacy Sandia VAWT research from 1973–95.