Application of Particle Image Velocimetry for the Investigation of High Speed Flow Fields

Abstract

For the past few years particle image velocimetry (PIV) has been increasingly used for aerodynamic research and development. This is mainly due to the unique feature of the PIV technique, which allows the recording of a complete velocity field in a plane of the flow within a few microseconds. Thus, PIV provides information about unsteady flow fields, which is difficult to obtain with other experimental techniques. The short acquisition time and fast availability of data reduce the operational time, and hence cost, in large-scale test facilities. Technical progress made in the last years allowed the PIV teams of DLR and ONERA to develop reliable, modular PIV systems for use in low speed wind tunnels. The application of PIV in high-speed flows poses a few more problems, mainly due to limited optical access in the test facilities. This paper will briefly summarize the state-of-the-art of PIV by describing the basic features of a PIV system and will present some results of recent PIV applications within industrial projects in low speed flows. An application of PIV in ONERA’s S2 wind tunnel, which has jointly been performed by ONERA and DLR, will be utilized to illustrate the state-of-the art of PIV in transonic flows.