Aerodynamic Coefficients of Free-Flying Cubes in Hypersonic Flowfield

摘要

Aerodynamic coefficients of a cube depending on a broad-range attitude change have been measured using the free-flight technique in a hypersonic flowfield. Experiments were performed therefore in the hypersonic wind tunnel H2K at the German Aerospace Center (DLR) in Cologne. The free- flight technique in H2K has allowed achieving a continuous rotation of the cube without any sting interferences in a broad angular range of 90 degrees. This motion of themodel during the free flight has been acquired using a nonintrusive high-speed stereo tracking system. A marker- based tracking algorithm has been applied to reconstruct the three-dimensional flight trajectories and attitudes to determine the resulting forces andmoments. By using high- speed schlieren photography, the unsteady flow structures have been recorded. Pitch-angle-dependent aerodynamic coefficients of rotating cubes have been observed.