Erkan Orman is a lecturer at Anadolu University, Faculty of Aeronautics and Astronautics in Turkey. He received his Master’s degree in the area of wind turbines from Anadolu University in 2010. His research interests include low Reynolds number flows, computational fluid dynamics, turbo machines; wind turbines, unmanned aerial vehicles with research focuses on shape optimization, geometry parameterization and optimization algorithms.
Aerodynamic shape optimization of an airfoil has a crucial role for wind turbines in order to increase blade efficiency for the whole range of blade pitch angles. In this study, NACA 4415 airfoil has been optimized by a genetic algorithm coupled with an airfoil analysis code. Geometry of the airfoil is represented by a PARSEC parameterization method to be able to generate different airfoil shapes. A matlab routine was developed to generate different airfoil shapes as individuals and to control the whole optimization processes. Lift to drag ratio obtained by the analysis code is chosen as fitness function of each individual. The aim of the optimization process is to find the PARSEC parameters which give the maximum of lift to drag ratio in a certain solution space. The flow is assumed to be in viscid and uniform for the sake of simplicity. Mach number and Reynolds number are chosen as 0.03 and 350,000 respectively. Angle of attack interval is chosen as between2° and 5°. Tournament selection method is used to select the individuals which have high fitness values for the next generation. The genetic operators; cross-over and mutation rates are chosen as 0.45 and 0.05 respectively. The code can be executed until a pre-defined iteration number or a certain convergence criteria were obtained. The results have showed that the final geometry obtained after the optimization process is superior to the original geometry for the specified angle of attack interval.