DRAG REDUCTION OF BLUNT TRAILING-EDGE AIRFOILS

Abstract: Wind tunnel experimentation and Reynolds-averaged Navier-Stokes simulations were used to analyze simple, static trailing-edge devices applied to an FB-3500-1750 airfoil, a 35 % thick airfoil with a 17.5 % chord blunt trailing edge, in order to mitigate base drag. The drag reduction devices investigated include splitter plates, base cavities, and offset cavities. Splitter plate lengths between 50 % and 150 % of the trailing-edge thickness and plate angles (±10◦) were investigated and shown to influence the lift and drag characteristics of the baseline airfoil. Drag reductions on the order of up to 50 % were achieved with the addition of a split-ter plate. The base cavity demonstrated possible drag reductions of 25%, but caused drastic changes to lift, primarily due to the method of device implementation. The offset cavity was shown to improve on the drag reductions of the splitter plate, while also eliminating unsteady vortex shedding prior to airfoil stall. 1 Jonathon P. Baker and C.P. van Da