Numerical Simulation of Harmonic Pitching Supercritical Airfoils Equipped with Movable Gurney Flaps

A two-dimensional numerical investigation was performed to determine the effect of an active Gurney flap on an oscillating supercritical RAE 2822 airfoil in transonic flow. The Navier-Stokes code Fluent was used to calculate the flow field around the airfoil using the Shear Stress Transport turbulence model. Dynamic simulations were based on a moving C-grid, whose harmonic pitching motion was managed using a compiled User Defined Function. Both effects of height and chordwise positioning were considered in this study. The heights of Gurney flaps ranged from 1% to 3% of airfoil chord lengths, while position ranged from the trailing edge to 10% upstream from the trailing edge. In comparison with the Baseline airfoil, the effect of the deployable Gurney flap is to enhance significantly the maximum lift and pitching-moment coefficients; however, an increment in the drag coefficient is also registered. The results indicate that the Gurney flap provides best performance close to the stall angle of attack.