DENSITY-MEASUREMENTS IN AN EXPANDING FLOW USING HOLOGRAPHIC-INTERFEROMETRY

A nonequilibrium expansion of nitrogen through a two-dimensional nozzl e of a reflected shock tunnel is investigated with laser holography, t ime-resolved pressure measurements, and emission spectroscopy to chara cterize the flowfield for future vibrational relaxation measurements. A two-dimensional computation is used to simulate the nozzle flowfield . Synthetic holograms are generated using the computed density profile s and are compared with the experimental holograms. Also, using a quas i-one-dimensional approximation, populations for each vibrational leve l are computed by 1) solving the master equations, and 2) using the La ndau-Teller formulation. Computational accuracy of both models is asse ssed against the experimental data.