Turbulent Boundary Layer Imaging in High-Speed Flow with a Megahertz Pulse-Burst Laser

Abstract

The measuring and modeling of turbulent boundary layers is critical to the study of aerodynamics. Examining the phenomena contained therein with high-speed flow is a particular challenge. To image turbulent boundary layers under these flow regimes and obtain flow properties, a megahertz-rate imaging system was created that leveraged filtered Rayleigh scattering to provide necessary temporal and optical resolution. After careful optimization of the relatively high-power pulse-burst laser system, the laser was tuned to lock onto the absorption spectrum of an iodine cell and then combined with a megahertz camera. The imaging of turbulence was ultimately successful in supersonic flow, but further work will be required to generate complete 2D boundary layer images.