Numerical Investigation of Influence of Diverse Winglet Configuration on Induced Drag

Abstract

In this study, numerical calculations were conducted over 3D wing surface with varying winglet configuration and their modifications to understand effect of wingtip device on induced drag formation. NACA0012 airfoil was used for all configurations due to availability of experimental lift and drag data. Lift, drag and pressure coefficient were calculated with SST turbulence model at the Reynolds numbers of 6 x 10(6) and were compared with experimental data to validate the simulation accuracy of numerical approaches. The winglet with different relative angle with wing surface was designed, and numerical calculation was performed with commercial software COMSOL. The winglets attached to the wingtip were divided into 3 different categories such as single winglet up or down sloping, split winglet up and down sloping. To see normal wingtip vortex, conventional wingtip was simulated together with winglet in all cases. Pressure coefficient for the midline section of the wing is in a good agreement with the experimental data, but pressure coefficient at the tip section is very different. Maximum size of vortices was observed for the case of winglet 45 degrees up sloping with the surface, but with the increasing winglet angle with the surface, size of vortex decreases. Results indicate that wingtip vortex formation was reduced considerably at the angle of attack relative to wing surface starting from 90 degrees and considering only lift and pressure coefficients, up-sloping winglet can be considered to be more efficient than down sloped one and maximum efficiency increased between 4 and 6%.