Free-Form Design of Low Induction Rotors

This work investigates an integrated free-form approach for the design of wind turbine blades, and its application to low induction rotors. In the free-form methodology, the airfoil shapes are treated as unknowns and optimized together with the other blade design parameters including chord, twist and the thickness of the structural elements. As the design of the airfoils automatically adapts to the evolution of the blade, it is possible to better explore the solution space and to obtain improved solutions that find better compromises between the aerodynamic and structural points of view. This process is here employed to evaluate low induction rotors as a possible way of designing very large wind turbines, and demonstrated through case studies concerning wind turbines up to 10 MW.