Recent developments of optical measurement techniques for wind tunnels at DLR Göttingen

During the last decade several advanced non-intrusive image based measurement techniques such as pressure sensitive paint (PSP) for pressure measurements on the complete surface of a model in the wind tunnel, particle image velocimetry (PIV) for large field and instantaneous velocity measurements, Temperature Sensitive Paint for transition line detection and various methods for model deformation measurement have been developed. Non-standard video techniques support qualitative visualization as well as the application of the image based quantitative measurement techniques at high speed or periodic events. Due to the fast progress made in the field of computers, lasers, electronics, video technique etc. in the past decade it was possible to set up reliable, modular and mobile advanced measurement systems for use in industrial test facilities such as large wind tunnels. Today PIV and PSP are the most advanced and mostly used of these techniques in industrial wind tunnels. The qualitative and quantitative improvements achieved during the past few years will be demonstrated taking application of these techniques in industrial wind tunnels as an example