Airfoil Design Using Genetic Algorithms

Genetic algorithms (GAs) are a search method used in finding true or approximate solutions to optimization and search problems. They have been applied in different fields like computer science, engineering, and economics. Here, we apply GA to the problem of designing a symmetric airfoil with high lift coefficient. Each population member, or chromosome, is an array representing the geometry of the airfoil. The optimization technique is applied to an initial population of airfoils having the geometry of NACA 4-digit series with different thickness ratios. Different GA operators are used including reproduction, binary encoding, crossover, and decoding. The flow field around the airfoil is solved using the finite difference method. The computational fluid dynamics (CFD) solver and the GA technique are combined together and yielded an optimal airfoil under certain optimization parameters. Different issues that arise from this process are discussed, like the necessity to add constraints to avoid unacceptable airfoil shapes.