Application of Temperature Senstive Paint (TSP) technology for investigation of boundary layer transition in short-duration wind tunnels is presented. Investigations were made on sharp and blunted §at plates in UT-1 wind tunnel of TsAGI operated in Ludwieg scheme at Mach numbers 5, 6, and 8 (Reynolds numbers from 5.5 · 10 6 to 26 · 10 6 ). Both natural and induced boundary layer transitions were investigated. BACKGROUNDTemperature Sensitive Paint method is a very e¨ective optical technique for heat §ux measurements. It provides the pattern of heat transfer rates on the whole visible model surface that is essential for three-dimensional (3D) §ows. In few recent years, this technique is successfully developed in TsAGI for short-duration wind tunnels [1,2].Temperature Sensitive Paint is a specially developed paint containing speci¦c luminophore which luminescence depends on temperature. Being excited by the light of appropriate spectral range, the TSP emits the luminescent light of longer wavelength range, and luminescent light intensity decreases with an increase of temperature. Thus, the temperature distribution can be determined in each point of investigated surface from noncontact optical measurement of TSP luminescence intensity by acquiring an image of the whole investigated surface. But luminescence intensity depends not only on temperature but also on excitation light intensity and TSP thickness. To exclude an e¨ect of excitation light intensity and TSP thickness, it is necessary to acquire second reference image of investigated surface at known temperature. Normalization of active image (acquired at unknown temperature distribution) on reference image exclude an e¨ects of Progress in Flight Physics 3 (2012) 15-24

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The §ow structure and heat transfer on sharp and blunted plates near a wedge have been studied experimentally at Mach number 6 and two Reynolds numbers corresponding to laminar and transitional boundary layers ahead of the wedge. Similarly to the two-dimensional (2D) §ow, the plate£s blunting causes a decrease of heat transfer at threedimensional (3D) interference between the boundary layer and the shock wave. However, there is a threshold bluntness value beyond which the in §uence is negligible. Heat transfer and pressure measurements as well as surface §ow visualization have been performed by means of panoramic (global) methods based on the use of luminescent coatings. They have been used in a short duration (pulse) wind tunnel for the ¦rst time.

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