Robust aerodynamic optimization strategies for rotor blades morphing airfoils

An aerodynamic optimization method is developed to define robust shapes for morphing airfoils for helicopter blades. The morphing strategy consists of a conformable camber airfoil which changes over the period of rotation of the blade to cope with the variable flow conditions encountered in forward flight. A robust or uncertainty-based approach is used to compute a reliable morphing airfoil, providing a low variance with respect to uncertainty affecting the operating conditions. In order to assess the effectiveness of the robust method, several optimization problems are performed, from a classical two-point drag minimization with lift coefficient constraint to a robust morphing camber optimization. The results of the optimization problems are compared and discussed to highlight the features of the robust approach.

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