Non-intrusive optical diagnostic experiments for high-speed flow generator flowfield characterization

Abstract

Two non-intrusive optical diagnostic methods, electron beam fluorescence (EBF) and focused schlieren (FS) have been set up and utilized for high-speed flow characterization and visualization of the High-speed Flow Generator (HFG) at NASA LaRC. Using the EBF technique, we were able to visualize and calculate several parameters of the low-density, free jet expansion of N 2 gas through a 5.0 mm nozzle. We also developed a high-sensitivity FS system to see shock structure in front of a spherical barrier and roughly determine the lower limit of its capability to visualize the N 2 flowfield.