Optical measurement techniques for flow field investigations

Particle image velocimetry (PIV) is increasingly used for aerodynamic research and development. The PIV technique allows the recording of a complete flow velocity field in a plane of the flow within a few microseconds. Thus, it provides information about unsteady flow fields, which is difficult to obtain with other experimental techniques, especially at the investigation of boundary layers, wake vortices, rotor flow fields and propeller slipstream. The development and application of a stereoscopic PIV system was described. The principles of the video stroboscope and of the model deformation techniques have been describe