APPLICATION OF PRESSURE-SENSITIVE PAINT IN SUPERSONIC NOZZLE RESEARCH

An experimental study was conducted to evaluate the pressure-sensitive paint (PSP) technique as a means of obtaining global surface pressure distribution on the inside surface of a supersonic nozzle at NASA Lan gley Research Center, In this experiment, the PSP technique was used t o measure the surface pressure distribution for several configurations of a convergent-divergent nozzle, which was also instrumented with a densely packed array of pressure taps. The PSP and pressure tap data w ere obtained simultaneously for each configuration of the nozzle, at s everal nozzle pressure ratios, to determine the effects of supersonic cavity-ramp vortex generators on the nozzle now and performance, Resul ts from the PSP data agreed very well with the pressure tap data and i ndicated that a pair of counter-rotating vortices were shed from the c avity vortex generator, The presence of these streamwise vortices caus ed a delay in the formation of the shock wave inside the nozzle.