This is an excerpt from the Fourth Quarter 2013 edition of the Wind Program R&D Newsletter.

Research conducted by the U.S. Department of Energy's Sandia National Laboratories revealed that leading-edge erosion on wind turbine blades can have a detrimental effect on wind turbine aerodynamic performance within the second year of operation. Light erosion may lead to a 5% decrease in annual energy production, and heavy erosion may reduce energy production by as much as 25%.

The leading-edge erosion project, part of the Blade Reliability Collaborative organized by Sandia, has sought to study and quantify the effects of blade erosion on wind turbine performance. Field measurements of leading-edge erosion on commercial wind turbines were used to drive the design of an airfoil model with a replaceable leading edge. Figure 1 shows the three leading-edge configurations that were applied to the airfoil model. Multiple wind tunnel test campaigns in the Texas A&M Oran W. Nicks Low-Speed Wind Tunnel produced an array of data, including the influence of different types of surface roughness on airfoil characteristics. The influence of the low roughness height on the location of the transition between laminar and turbulent flow on the airfoil model is important because it drives airfoil performance characteristics, such as the lift curve and maximum lift, which determine overall wind turbine performance. Wind tunnel results indicated that the influence of roughness heights on the airfoil lift curve may cause a substantial decrease in lift at higher angles of attack, where wind turbines operate. Through a collaborative effort, the results from these tests are being used to calibrate and verify computational models under development at the University of California, Davis.

To read more about Sandia's wind turbine blade research read Realistic Leading-Edge Roughness Effects on Airfoil Performance.