Insight aerodynamic analysis on small-scale wind turbines airfoils for low Reynolds number applications

The selection of low Reynolds number airfoils for the application of small wind turbine rotor that results in greater rotor performance to the given operating condition is monotonous process. The 16 low Reynolds number airfoils specially developed for small-scale wind turbine applications were shortlisted to determine the optimum set of airfoils for designing the 3 bladed and 2.25 m radius rotor with the tip speed ratio of 7. Numerical studies were conducted using subsonic airfoil design and analysis solver XFOIL. The aforesaid analysis was done for the Reynolds number of 49,637, 72,801, 115,820, 132,366, and 169,869, which are calculated from the velocity triangle for the subsequent free stream wind speed of 3, 4, 5, 6, and 7 m/s that represents the urban wind condition of India. The indispensable characteristics to improve the performance of wind turbines such as maximum lift to drag ratio, insensitivity to optimum angle of attack over a range of Reynolds numbers and linear transition locations are present in SD7037, E193, SD7032, A18, E387, SD7062, E193MOD, S1210, and S1223 airfoils. Detailed investigation on the aerodynamic characteristics and the effect of laminar separation bubble (LSB) on each airfoils would be helpful to identify the airfoils which needed to be studied for the further improvement of performances through grooving and gurney flaps.