Numerical Comparison of Turbulence Models For a Naca 0012 Aerofoil With Gurney Flap

This study presents a computational investigation on the aerodynamic behavior of a NACA 0012 aerofoil equipped with a 1.5%c height Gurney flap, utilizing various turbulence models in ANSYS Fluent. Five widely recognized turbulence models—Spalart-Allmaras, Standard k-ε, Realizable k-ε, SST k-ω, and Transition SST—were employed to assess their predictive accuracy under identical flow conditions. The primary objective was to determine the most appropriate model to capture the aerodynamic effects caused by the trailing-edge Gurney flap, particularly in terms of lift coefficient, drag coefficient, and lift-to-drag ratio. A mesh independence study was conducted to ensure numerical reliability, and the results were interpreted considering prior studies that investigated Gurney flap performance on symmetric airfoils. According to results, it is demonstrated that the Transition SST model provides the highest aerodynamic efficiency from 0° to 4° while k-ε Realizable model gives the best of that after 6o until 12o. Among the models investiagted, the k-ε Realizable model exhibited superior consistency in predicting both lift enhancement and flow separation behavior. The findings reveal that the k-ε Realizable model, which yields the highest lift-to-drag ratio (CL/CD) particularly at an angle of attack of α = 8°, is the most suitable turbulence model for CFD-based aerodynamic optimization studies involving passive flow control devices such as Gurney flaps. In this context, this study provides an important perspective on turbulence model selection for low Reynolds number applications.