Further developments of pressure sensitive paint (OPMS) for non flat models in steady transonic flow and unsteady conditions

To achieve the 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 2 mbar 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, since then it also becomes possible to evaluate wall shear stress. 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.