In today’s wind energy market and for a variety of reasons, vertical-axis wind turbines, such as the Savonius and Darrieus Rotors, have found limited use when compared to conventional, horizontal-axis wind turbines. However, new vertical-axis designs are emerging that might provide significant power generation benefits for specific, remote-area, lower-wind applications. One such configuration is a geodesic spherical design, providing advantages in manufacturing using lightweight materials, and taking advantage of a sphere’s structural stability. In constructing this design, a critical decision is the type of airfoil used to drive the device. This research chronicles the performance of the s1210 airfoil, using wind tunnel experimentation at low Reynolds Numbers. The objectives of this research were to (1) formalize a methodology to quantify the aerodynamic performance of the s1210 through 360 degrees’ angle-of-attack, (2) characterize any effects of wind-tunnel wall interference with the airfoil itself, and (3) compare the s1210’s performance with another type of airfoil. Lift and drag data were collected for the s1210 at low Reynolds Numbers throughout a full rotation of the airfoil. Wind tunnel interference was accounted for using standard correction methods. Using a coordinate transformation, the magnitude of the driving, force was then determined. By applying a curve-fit to the data, parametric equations were generated to predict the aerodynamic forces at any location during the rotation of the turbine. These results show that the s1210 produces a driving force in three of the four quadrants of rotation. The third objective, comparing two airfoils, is still in progress.
Dr. D. Blake Stringer
In today’s energy market, vertical-axis wind turbines have limited use when compared to horizontal-axis turbines. However, new designs are emerging that might provide significant power generation for lower-wind applications. One configuration is of spherical design, in which the type of airfoil used is of importance. This research chronicles the wind tunnel experimentation of the s1210 airfoil. The objectives were to formalize a methodology to quantify the performance of the s1210 through 360 degrees’ angle-of-attack, and characterize any effects of wind-tunnel interference. Aerodynamic performance data was collected for full rotation of the airfoil. Wind tunnel interference was accounted for using correction methods. Using coordinate transformations, the driving force magnitude was determined and shows the s1210 produces a driving force in three of four quadrants of rotation.