Prediction of Aerodynamic Characteristics of an Elliptic Airfoil at Low Reynolds Number

This study focuses on modeling the effects of transitional flow and surface curvature on aerodynamic characteristics of an elliptic airfoil. Numerical simulations have been performed on a 16% thick elliptic airfoil for a range of angle of attack (a) from 0 to 20 and flow Reynolds number (Re) of 3 x 10(5), using relatively new transition-sensitive and traditional fully turbulent eddy viscosity turbulence models. Test conditions were matched to experiments by Kwon and Park (2005) and numerical results were compared with available experimental data. Results indicate that the transition-sensitive models, namely kappa-kappa(L)-omega and Transition SST, accurately predict the laminar-to-turbulent transition locations and reproduce the laminar separation bubbles on the suction surface of the airfoil in agreement with the experimental data. Also, transitionsensitive models yield improved predictions of lift and drag performance when compared with results from fully turbulent models. The fully turbulent models; including SA and kappa-omega SST, and a newly developed curvature-sensitive model (SST kappa-omega-upsilon(2)) fail to capture the flow separation and reattachment locations near the leading edge of airfoil. However, the curvaturesensitive SST kappa-omega-upsilon(2) model predicts the stall point of the airfoil close to experimental results, while all other tested RANS models failed to accurately predict the stall point. Taken as a whole, the results suggest that accurate aerodynamic predictions at both low and high angles of attack might be achieved by using a model that includes the effects of both transition and curvature.