The Effect of Blade Roughness on Wind Turbine Performance

In this study, the effect of various degrees of blade roughness on the performance of horizontal axis wind turbines is investigated analytically. The roughness effects are analyzed in terms of the annual energy output and cost effectiveness. A computer model has been developed to quantify the effects of roughness. The model incorporates a correlation of experimental airfoil data for any degree of roughness and Reynold's number. Additionally, procedures for reducing surface roughness effects based on blade pitch variations have been evaluated. Three turbines, with rated power outputs of 25, 400, and 2000 kW, are cited as case studies to illustrate surface effects.