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 various complex flow phenomena. Two examples of interactions will be addressed in the present paper: A) the characterisation of the wake of a counter rotating ultra high-bypass fan (CRUF) TPS where experimental data served for a comparison with and a validation of CFD calculations and B) the use of time-resolved PIV data achieved in the flow around a trailing edge as an input for sound pressure wave emission calculations by CAA. Both parts A )”TPS study” and B) “Trailing-edge noise study” will be described independently.