Particle Image Velocimetry as Validation Tool in Aeronautics

Abstract

PIV is an advanced optical measurement technique which allows measuring large numbers of instantaneous velocity vector fields in a plane or volume of a flow with high spatial resolution and within short wind tunnel run times. From these velocity fields it is possible to calculate averages and related RMS- and fluctuation velocity fields, vorticity and other derivatives or products of fluid mechanical significance. PIV data are therefore well suited for validation of numerical codes. In several aeronautical research projects CFD, PIV and other experimental measurement techniques have been used jointly in order to capture a more holistic image of the complex flows e.g. around high-lift-configurations (EUROLIFT 2), behind TPS- (CRUF) or propeller flows (HICON). In the presentation we will show some examples of interactions between numerical and experimental investigations where experimental data served either for a comparison with, a validation of or as input for CFD or CAA calculations. As an outlook for future cooperation of simulation tools and velocity measurements a most recent development of the PIV technique, which delivers instantaneous 3D velocity vector volumes and therefore the full velocity gradient tensor, will be explained and demonstrated at a turbulent boundary layer.