Application of the PSP technique in low speed wind tunnels

Results of pressure field measurements on the A400m half model in the low speed wind tunnel of Airbus Bremen, Germany, are presented. The model is equipped with two propeller simulators driven by pressurized air. The great challenge was to compensate the influence of the warm and cold air pipes which are guided inside the wing, creating large temperature differences on the models surface. The PSP (pressure sensitive paint) measurements were carried out with the mobile DLR PSP system using the DLR02 paint formulation. The influence of propellers with different thrust levels on the pressure distribution was determined successfully. An assessment of the accuracy of the results can be performed by comparison of PSP data with conventional pressure tap data