Lift Enhancement of the LRN 1015 Airfoil using a Gurney Flap: A Computational Fluid Dynamics Investigation
Authors: Lemuel F. Banal and Aristotle T. Ubando
Abstract
A Gurney flap is a small tab installed at the trailing edge of a wing to enhance the lift of an airfoil. The LRN 1015 airfoil has a high lift-todrag ratio but is not considered to be a high-lift airfoil. If its lift is improved, additional benefits such as reduced take-off and landing roll, reduced stalling velocity, and increased payload capacity, among others, can be gained. In this light, the effects of the integration of the flap into the airfoil were investigated using a computational fluid dynamics approach. Part of this study is the validation of the computational fluid dynamics model used through investigation of the unflapped airfoil using ANSYS
CFX with a Shear Stress Transport k-ω turbulence model, and comparison of the results with wind tunnel data. The same computational model was used to investigate the effects on the airfoil performance of the flap with heights of 1.58%, 2%, 3% and 4% of the chord. Results revealed that 46% increase in the maximum lift coefficient was achieved by a flap height of 3% of the chord, at a Mach number of 0.2 and a Reynolds number of 500,000. In addition, the drag and the pitching moment were also increased, but no degradation in the lift-to-drag ratio was observed for low angles of attack typically used for cruise.