In the past decades several image based measuring systems have been developed for industrial aerodynamic research and in addition to classical wind tunnel measurement methods. These advanced optical and image based techniques are capable to deliver field data of the related physical
quantities in a non- or minimal intrusive way: Pressure sensitive paint (PSP) is able to measure pressure distributions on the surface of models, marker based systems are measuring the position of the model during wind tunnel operation, image pattern correlation technique (IPCT) is even able to capture the surface deformation like bending and twist of airfoils quantitatively, temperature sensitive paint (TSP) images show transition line positions e.g. on a wing surface, microphone array techniques are creating maps of sound sources in various frequency domains along the model, background oriented Schlieren (BOS) can detect density gradients present at shocks and along vortex lines and,
last but not least, PIV delivers a large number of instantaneous velocity vector fields in planes within the flow field in short wind tunnel run times. All these techniques give valuable information about the status of the fluid mechanical field around or its effects on a model in a wind tunnel test and have been developed for mobile use at DLR in Gottingen.