Aerodynamic Investigations in Low and High Speed Wind Tunnels by means of Particle Image Velocimetry

Particle Image Velocimetry (PIV) is increasingly used to investigate unsteady velocity fields instantencously. For the first time the PIV technique allows the recording of a complete velocity field in a plane of the flow within microseconds. This does not only give information about unsteady flow fields otherwise not obtainable but also helps to save operational time in the wind tunnel. At DLR a set up for PIV has been developed which can be operated under the rough environmental conditions (noise, vibrations) of a large wind tunnel. This system has been successfully applied to low speed as well as to high speed flows (U = 10. 500 m/s). The evaluation and post processing of the PIV recordings run fully automatical on a workstation.