Design method for wind turbine airfoils by adjoint optimization considering climate conditions

Power extracting has led the world to deal with serious environmental issues. However, the wind is a clean renewable source for power extracting, which is promising for diminishing those issues. Some previous effort has been made to increase wind power extraction by designing more efficient airfoils. Nonetheless, there is a lack of considering the climate conditions for the design process. Therefore, this study's main objective is to suggest a methodology for wind-turbine airfoil design, which takes into account the flow condition of the location where the turbine would be settled, applying the adjoint optimization method together with CFD technics. The first step was to propose a method for calculating the Reynolds and Mach number used in the CFD simulations for wind turbine airfoil design, regarding geographical conditions and wind distributions. Next, the CFD code was validated by comparing numerical simulations to wind tunnel results. Then, the adjoint optimization method was tested for the numerical model comparing to a SU2 Test Case in order to verify the model's results coherence. Finally, the method was applied for NACA 0012 airfoil for different climate conditions. The optimization yielded aerodynamic efficiency improvements ranging from 7.6% to 9.5%, leading the optimized NACA0012 to become 11% more efficient than the often-used wind turbine airfoil S809 within the considered flow conditions. However, differences between optimized airfoil shapes for distinct climate conditions were not remarkable.