Low Reynolds Number Airfoil Design for a Mars Exploration Airplane Using a Transition Model

Abstract

In this study, the design optimization of a low Reynolds number airfoil is performed for a Mars exploration airplane. To achieve this goal, a multi-objective genetic algorithm (MOGA) using the Kriging model is used for optimization and a γ–Re_θ model is adopted to predict the laminar-turbulent transition point on the airfoil. Both PARSEC and NURBS representations are used to define the geometry of the airfoil in order to investigate its effect on the transition delay. The aerodynamic performances of the airfoils designed are compared with those of the ss1f airfoil, which was designed for the Mars exploration airplane during the ARES project. The objectives of optimization are to minimize the drag coefficient with a fixed lift coefficient and to minimize the moment sensitivity with respect to the angle of attack. Transition of the airfoil using the PARSEC representation occurs further downstream than that of the ss1f airfoil. Furthermore, the airfoil using the NURBS representation achieves fully laminar flow on the upper surface. The moment sensitivity of the optimized airfoils is also lower than that of the ss1f airfoil.