Supercritical Wing Design and Optimization for Transonic Civil Airplane

Numerical Optimization based on high-fidelity Computational Fluid Dynamics method is used for the super-critical wing design and optimization. NSGA-II is used for optimization. In the optimization process, geometries of the airfoils are deformed by attaching NURBS based increment functions to the basic airfoils' expression. With the idea of increment functions, "cut and try" by designers and numerical optimizations can be united. Design results with single point and multi-point are compared. With the single point (minimum cruise drag coefficient) optimization, the cruise drag can be decreased by about 3 drag counts. On contrast, the multi-point design (minimum drag coefficients at both the cruise and the preset Drag Divergence Mach number (DDM)) can gain more than 10 counts drag decrease at DDM, with a 3 counts penalty in cruise drag. Design results of the multi- point optimization are quite insensitive to the velocity disturbance and therefore much more engineering applicable.