EFFICIENT MULTI-OBJECTIVE DESIGN OPTIMIZATION OF ROTOR AIRFOILS FOR IMPROVING DYNAMIC STALL CHARACTERISTICS

The dynamic stall characteristics of an airfoil limit the aerodynamic performance of a rotor. To improve the dynamic stall characteristics of the rotor airfoil, an efficient multi-objective aerodynamic shape design optimization method for rotor air foils based on Computational Fluid Dynamics and numerical optimization algorithms is developed. This method employs the efficient surrogate-based multi-objective optimization(SBMO) algorithm, which enhances optimization efficiency and convergence through decomposition and cooperation. The perturbed CST method was used for airfoil parameterization. By applying the developed method, the optimized airfoil showed significant improvement in dynamic stall characteristics, with the peak pitching moment coefficient reduced by 38.8%. Additionally, a multi-objective optimization design considering both dynamic stall characteristics and static aerodynamic characteristics in hovering was conducted, resulting in a Pareto front with 33 solutions. The optimal airfoils selected from this Pareto front focus on different aerodynamic characteristics. One selected airfoil effectively balances both aspects, reducing the peak pitching moment coefficient by 19.71% and the static drag coefficient in hovering by 10.70%.