Pressure Sensitive Paint Measurements in DLR's Transonic Wind Tunnel in Goettingen.

Abstract

With a new "resection" method the PSP results were accurately measured and compared with conventional pressure tap measurements. To achieve the diner calibration of pressure sensitive paint of a coated model in the wind tunnel, using the pixel by pixel calibration, a resolution of absolute pressure up to 2mbar in comparison to the conventional PSI technique is possible. However, this is only achieved by using an image processing method for removing image distortions and recording the surface temperature of the model simultaneously. In this case an angular influence of illumination or the resulting emission will be compensated automatically. The results obtained show that in the immediate future the range of application will extend from subsonic into the hypersonic regime. Furthermore, the simultaneous recording of surface temperature will play an increasing role. For exact measurements of unsteady flows a first step was made to acquire periodic flow phenomena. The use of extremely sensitive low-noise video cameras will certainly allow surface pressure measurement of such processes in the future.