Optimization procedure for wings flying in the Martian atmosphere

Long-endurance fixed-wing drones for Mars exploration require customized wing sections and planform layout to maximize the aerodynamic efficiency. In this framework, the paper deals with the aerodynamic shape optimization of a wing designed for a concept drone operating in the Martian atmosphere. An in-house procedure, which uses a Free-Form Deformation method to parametrize the wing section and combined with a parametric model of the wing planform, is developed to support the optimization process. The maximization of the aerodynamic efficiency for a cruise flight performed at M infinity = 0.3 and Re infinity = 60 x 103 is assumed as design objective. Optimization stages are performed using a genetic algorithm supported by Design-of-Experiment and response surface methodologies. The critical Mach number, the wing mass, and the pitching moment are assumed as design constraints. Two different candidates with (L/D)max have been found by the optimization procedure. Assessment of aerodynamic performance of optimal candidates is performed with OpenVSP toolkit, calibrated using computational fluid dynamic simulations for a test wing at Re infinity = 45 x 103. Optimization trends, correlating cambered airfoils and swept angles to specific values of angle of attack, are highlighted indicating possible design improvements in the low-Reynolds flight regime.