Comparison of water and wind tunnel flow visualization results on a generic fighter configuration at high angles of attack

Abstract

Flow visualization experiments were performed on a series of generic fighter configurations at medium to high angles of attack in both a w ater tunnel and a w ind tunnel. The models were tested originally in a w ater tunnel to investigate methods for controlling the forebody and wing/LEX vortices for airframe control augmentation at high angles of attack. The same models were subsequently tested in a low-speed wind tunnel at the identical Reynolds number to compare the core locations and burst points of the LEX and wing vortices in the two test mediums. A u nique application of a smoke flow visualization method used primarily in low-speed wind tunnels for two-dimensional airfoil flow visualization was adapted to provide a direct means for comparison to the dye-flow results from the water tunnel. Direct comparisons of photographs from the two tests at various angles of attack on three different configurations showed nearly identical flow fields, confirming expectations that the test medium should have n o bearing on the flow field structure.