Application of PSP in low speed flows

Since low speed tests play an important role for the design phase of aircraftʹs, the PSP technology has to be developed also for small pressure variations in the pressure range between 800 and 1000 mbar. Several tests at ONERA and at DLR have been performed to optimize the PSP system components and the paints. Tests on different models like basic aircrafts or parts of them and car models are presented. A careful choice of the paint as well as a specialized procedure and a devoted software have provided accurate results, with a maximal error of ±1 mbar. Calibration methods were developed to optimize the accuracy. in sources of errors have been identified and their relative importance has been assessed. As a result, a good agreement with conventional pressure taps is obtained. Fine details can be seen in the final pressure maps, showing the benefit of PSP for low speed tests down to 25 m/s.