Experimental and Computational Investigation of Blunt Trailing-Edge Airfoils with Splitter Plates

Abstract

Experimental and computational examinations of the effect of splitter plate length on the aerodynamic performance and vortex shedding behavior of a blunt trailing-edge airfoil are presented along with an evaluation of spanwise shedding coherence. The FB-3500-1750 airfoil, which has a maximum thickness of 35% chord and trailing-edge thickness of 17.5% chord, was tested in the University of California, Davis, Aeronautical Wind Tunnel at a chord Reynolds number of 666,000. The flow behavior was also examined computationally using OVERFLOW, a Reynolds-averaged Navier–Stokes solver. Splitter plates with lengths ranging from 50 to 150% of the trailing-edge thickness were applied to the airfoil model. Drag reductions of at least 27% from the baseline were observed with the inclusion of a splitter plate with length 50% of the trailing-edge thickness, accompanied by a 5% loss in maximum lift. An increasing splitter plate length was shown to decrease the base drag, maximum lift, and stall angle. The Strouhal number also increased with an increasing splitter plate length over the range examined. The spanwise correlation length of the vortex shedding was determined to be four to five times the trailing-edge thickness for both fixed and free transition at two different angles of attack.