Application of on-line particle image velocimetry to high-speed flows

Whole field velocity measurements of the flow past a NACA 0012 airfoil at high angle of attack are obtained by means of a particle image velocimetry, in both static and dynamic conditions. The 'On-Line' Velocimeter used for the measurements features a solid state imager, a microcomputer workstation and dedicated electronic bands. The Velocimeter is capable of acquiring, displaying and processing the multiple exposed frames. Using this novel approach the fully separated flow over the upper surface of the airfoil at high subsonic free- stream velocities (approximately 150 m/sec) was mapped.