Rayleigh imaging and flow tagging in ground test facilities

The authors present preliminary results on the application of ultraviolet Rayleigh imaging and RELIEF flow tagging to a high Reynolds number, Mach 3 blow-down air facility at Princeton University's Gas Dynamics Laboratory. RELIEF tagging was accomplished using stimulated Raman scattering to vibrationally excite oxygen molecules. Examples include instantaneous images of boundary-layer structure and shock-wave/boundary-layer interactions, as well as very recent results of flow tagging velocity measurements in the free-stream and boundary-layer regions of this facility. The future implementation of filtered Rayleigh scattering is also discussed.