On stealth airfoil optimization design for flying wing configuration

To deal with the diametrically different requirements between the aerodynamic and stealth design of a flying wing configuration, high fidelity methods are used to evaluate the aerodynamic performance and stealth characteristics of the foil, and a multi-objective optimization platform is established based on the Parsec method, radial basis function (RBF) neural network, Pareto genetic algorithm and the loose surrogate model management method. Diverse optimal objectives and constraints are raised on the capability and features of the inner and outer wing. An aerodynamic and stealth integrated airfoil optimization design investigation is carried out. The results show that for a flying wing with both good aerodynamic and stealth performance, the pitching moment and radar cross section (RCS) in the key azimuth of the inner wing can be reduced by camber, leading-edge radius, trailing-edge angle and thickness design. The upper surface of the outer wing affects transonic aerodynamic performance seriously, which should be designed carefully to improve aerodynamic efficiency, while more attention should be paid to the stealth performance in the lower surface. Some airfoil parameters show opposite effect on aerodynamic performance and stealth characteristics, and they should be chosen as the main design variables for integrated optimization. The Pareto front can provide multiple choices for 3D design.