Multi-Objective Optimization of Transonic Variable-Camber Airfoil with Leading and Trailing Edge Deflections Using Kriging Surrogate Model

To investigate the aerodynamic characteristics and multi-objective optimization of the variable camber transonic airfoils, the influence of leading and trailing edge deflection angles on aerodynamic performance is analyzed under different angles of attack and Mach numbers. A prediction model is developed based on a Kriging surrogate model, with leading and trailing edge deflection angles as inputs and lift coefficients and drag coefficients as outputs, NSGA-II multi-objective optimization algorithm is employed to determine the optimal deflection parameters for Mach numbers of 0.74, 0.75, and 0.76. The results show that leading edge upward deflection contributes to improve the lift-to-drag ratio, while downward deflection enhances the critical angle of attack. The trailing edge deflection has a relatively minor effect on the critical angle of attack, the downward deflection can improve the lift coefficient. Additionally, appropriate upward deflections of both the leading and trailing edges can delay the critical Mach number, while downward deflections of both edges can advance the critical Mach number. Compared to the basic airfoil, the optimized airfoil reduces the drag coefficient by 22.92%, 43.88% and 56.31% at the three Mach numbers, and increases the lift-to-drag ratio by 11.13%, 20.65%, and 24.89%, respectively, resulting in significant aerodynamic performance enhancement. The prediction errors between the Kriging model and simulation values are less than 6%, effectively improving computational efficiency.