Development of a Vertical Axis Wind Turbine (VAWT) Field Research Center to Investigate the Inner-Rotor Fluid-Structure Interactions

Abstract

A state-of-the-art vertical axis wind turbine (VAWT) research facility has been developed at theUniversity of Minnesota Duluth Research and Field Studies Center. The focus of this project is to develop a facility that is designed to address the deficit of field scale VAWT studies and provide a physical investigation to the characteristics of VAWTs, including the inner-rotor fluid dynamics and rotor-scale fluid-structure interactions. The research is driven by the outlook for renewable energy and the adoption of VAWTs for distributed wind, array clustering and offshore energy, among other applications. A 2.4kW H-Darrieus VAWT is mounted on a 19.8m (65ft) steel tower that is fitted with 3D sonic anemometers and meteorological sensors. There are three measurement stations at 6.1m (20ft), 12.2m (40ft) and 18.3m (60ft), which sample up to 32Hz. A high-resolution 3D sonic anemometer positioned inside the rotor location at 18.3m (60ft) samples up to 100Hz to capture 3D wind components enabling the potential for detailed vortex dynamic characterization. Atmospheric conditions are also sampled at each station at 1Hz. An initial investigation into the inner-rotor fluid dynamics illustrates the presence and ability to measure vortex dynamics and shedding from turbine blades. While this specific project designed the facility, the complex multi-parameter data acquisition system, and provided initial insights into VAWT inner-rotor vortex dynamics, a deeper investigation of this phenomenon should be conducted to evaluate how performance characteristics of the turbine are affected. Additionally, consideration of other atmospheric conditions should be considered alongside the inner-rotor fluid-structure interactions to expand the understanding of VAWT performance regions that experience large differences in meteorological conditions from season to season. The site experiences a vast number of atmospheric conditions. These conditions include extreme winds, icing events including rain, sleet and snow with historical maximum and minimum temperatures of 41.1°C (106°F) and -40.6°C (-41°F), respectively. It is also easily accessible providing the ability to be a cross-functional facility with education, outreach, and cross-disciplinary research with a focus to provide real-time open access data. Given the extreme conditions and ease of accessibility, the site is well suited to provide contributions to VAWT research and design.