Airfoil optimization based on low fidelity flow models

Direct airfoil optimization with single or multiple objectives is always required in preliminary aircraft design. Low fidelity aerodynamic methods like incompressible potential and incompressible boundary layer are still attractive when used under a genetic algorithm that although is relatively slow, it enables the identification of the global solution while handling generic constraints in a simple way. The work is focused on small angles of attack, for flows without large separations, where the current low fidelity models provide a good level of certainty. Geometric parametrisation of airfoils considers NACA 4, generic polynomial and a combination of Class Shape for thickness and Bernstein polynomials for camber line. Few objective functions are tested and it is shown with numerical results that constraint optimization is fully consistent at high Reynolds, achieving solution uniqueness according to engineering requirements, while for low Reynolds there is a need for special treatment.