Effects of Gurney Flap on Supercritical and Natural Laminar Flow Transonic Aerofoil Performance

The aerodynamic effect of a novel combination of a Gurney flap and shockbump on RAE2822 supercritical aerofoil and RAE5243 Natural Laminar Flow (NLF) aerofoil is investigated by solving the two-dimensional steady Reynolds-averaged Navier-Stokes (RANS) equation. The shockbump geometry is predetermined and pre-optimised on a specific designed condition. This study investigated Gurney flap height range from 0.1% to 0.7% aerofoil chord length. The drag benefits of camber modification against a retrofit Gurney flap was also investigated. The results indicate that a Gurney flap has the ability to move shock downstream on both types of aerofoil. A significant lift-to-drag improvement is shown on the RAE2822, however, no improvement is illustrated on the RAE5243 NLF. The results suggest that a Gurney flap may lead to drag reduction in high lift regions, thus, increasing the lift-to-drag ratio before stall.