Design and Experimental Results for the S814 Airfoil

A 24% thick, airfoil, the S814, for the root region of a horizontal-axis wind turbine blade, has been designed and analyzed theoretically and verified experimentally in the low-turbulence wind tunnel of Delft University of Technology Low Speed Laboratory, The Netherlands. The two primary objectives of restrained maximum lift, insensitive to roughness, and low profile drag have been achieved. Theconstraints on the pitching moment and the airfoil thickness have been satisfied. Comparisons of the theoretical and experimental results show good agreement with the exception of maximum lift which is overpredicted. Comparisons with other airfoils illustrate the restrained maximum lift and lower profile-drag of the S814 airfoil, thus confirming the achievement of the objectives.