Aerodynamic design optimization for low Reynolds tandem airfoil

A series of aerodynamic design optimization studies are performed to investigate the performance of two-dimensional tandem airfoil at low Reynolds number of 220,000. A total of 23 design variables, including decalage, gap, stagger, and airfoil profile variables are considered. Hierarchical evolutionary algorithm together with dynamic metamodel optimization is used to achieve the maximum lift-to-drag ratio for tandem airfoil. The studies investigate the impact of various design variables on optimized tandem airfoil. The results show that tandem airfoil in lower Reynolds flow has better aerodynamic performance at high angle of attack. And the lift-to-drag ratio can be further increased by 11.9% when airfoil profile variables are introduced. Morphing tandem airfoil can overcome low lift-to-drag ratio at lower lift coefficient, and is attractive for unmanned aircraft.