Unsteady Airfoil Design Optimization with Application to Dynamic Stall

One of the most persistent problems affecting the aerodynamic performance of rotorcrafts is retreating blade stall that results in large pitching moments and hazardous control situations. In this proposal our primary goal is the development of an unsteady design optimization framework that can be applied to refine rotorcraft blade designs by delaying the onset and severity of stall, and improve aerodynamic performance as well as lift cycle hysteresis. The proposed unsteady optimization framework utilizes an evolutionary algorithm, automated shape parameterization/deformation tool and a novel CFD derived analysis methodology for evaluating the objective function. The framework was deployed successfully for design optimization of pitching airfoils without stall in Phase I. In Phase II the framework will be applied to Multi-objective Optimization (MDO) studies and design studies of airfoils that undergo dynamic stall. Furthermore, the framework will be extended to include a probabilistic analysis method that quantifies the uncertainty associated with designs and includes experimentally derived data in the optimization loop. A GUI will also be developed to render designs, monitor the process in real time.