Aerodynamic multiobjective design exploration of a flapping airfoil using a Navier-Stokes solver

Aerodynamic knowledge for flapping airfoil is obtained by application of the multiobjective design exploration framework to a multiobjective aerodynamic flapping airfoil design optimization problem. The objectives of the design optimization problem are 1) time-averaged lift coefficient maximization, 2) time-averaged drag coefficient minimization, and 3) timeaveraged required power coefficient where the airfoil oscillates in plunging and pitching modes. Pareto-optimal solutions are obtained by a multiobjective evolutionary optimization and analyzed with the self-organizing map. Aerodynamic performance of each flapping airfoil is evaluated by a two-dimensional Navier-Stokes solver. Analysis of the flow over the extreme Pareto-optimal flapping airfoils provides insights into flow mechanism for thrust maximization, lift maximization, and required power minimization. Analysis of the design objectives and design parameters with the self-organizing map leads to useful guidelines for practical flapping-wing micro air vehicles. The present result ensures that the multiobjective design exploration framework is useful approach for real-world design optimization problems.