This article comes from Sandia National Labs Wind & Water Power News and is reposted with permission.
A new wind turbine blade has been designed at Sandia National Laboratories for the National Rotor Testbed (NRT) project and for future experiments at the Scaled Wind Farm Technology (SWiFT) facility with a specific focus on scaled wakes. The new blades can produce a wake similar to that of utility scale blades (of a 1.5-MW trubines) despite the difference in size and location in the atmospheric boundary layer. The overall aerodynamic design philosophy ensures that the NRT blade has the same dimensionless circulation distribution as a full-scale blade so that the wake is created by the same shed vorticity.
A predicted power coefficient of 0.47 is achieved through the use of efficient S825 and S814 airfoils, and a region 2 tip-speed-ratio of 9. The NRT preliminary design review will take place in late October 2015 with an external review committee. The accompanying image shows the blade shape as viewed from the tip and at an elevation angle of 30 degrees above the suction surface.