Thermofluidic Mechanisms of Aero-Optical Distortions in a Subsonic Compressible Shear Layer

The spatial and temporal density variations that are characteristic of a compressible free shear layer give rise to significant optical aberrations, leading to a reduction in performance of an optical system viewing through the flow. Previous experimental, computational, and analytical studies into the aero-optical effects of a compressible shear layer have shown disagreement in the magnitude and spatial distribution of density variations in the flow and, thus, the thermodynamic origin of the optical distortions. In this study, we leverage advanced computational fluid dynamics simulations to effectively investigate the thermofluidic interactions present in a compressible free shear layer and provide insight into the driving mechanism for the spatial variations that are observed in numerical and experimental realizations of density, static temperature, and total temperature.