Hierarchical Evolutionary Algorithms and Its Application in Transonic Airfoil Optimization in Aerodynamics

Hierarchical evolutionary algorithms based on genetic algorithms (GAs) and Nash strategy of game theory are proposed to accelerate the optimization process and implemented in transonic aerodynamic shape optimization problems. Inspired from the natural evolution history that different periods with certain environments have different criteria for the evaluations of individualsʹ fitness, a hierarchical fidelity model is introduced to reach high optimization efficiency. The shape of an NACA0012 based airfoil is optimized in maximizing the lift coefficient under a given transonic flow condition. Optimized results are presented and compared with the single model results and traditional GA.