High Magnification Telecentric Background Oriented Schlieren (BOS) and its Application to a Supersonic Turbulent Boundary Layer

Background oriented schlieren is a quantitative optical flow visualization technique that relies on the deflection of light due to density gradients in compressible fluid flows. An image of a dot pattern that is distorted by the schlieren object is compared to an undistorted reference image. The apparent local displacement of the dot pattern through the fluid flow can be extracted using cross-correlation-based techniques and used to calculate the density gradients. Using a telecentric optical system for BOS measurements has been shown to improve spatial resolution and better address three-dimensional effects compared to using a conventional entocentric optical system. In this work, methods for qualitative and quantitative comparison between telecentric BOS measurements and ILES simulations of a Mach 2 turbulent compressible zero pressure gradient boundary layer are investigated.