Investigation of Unsteady Flow Fields in Wind Tunnels by Means of Particle Image Velocimetry

Particle Image Velocimetry (PIV) is increasingly used to investigate unsteady velocity fields instantaneously. For the first time the PIV technique allows the recording of a complete velocity field in a plane of the flow within microseconds. PIV provides information aboutunsteady flow fields which is difficult to obtain with other experimental techniques. It 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 industrial wind tunnel. This system has been successfully applied to very low speed as well as to high speed flows(Uc. 600 m/s). The evaluation and post-processing of the PIV recordings run fully automated on a workstation