Aero-optical measurements in a subsonic, turbulent boundary layer with non-adiabatic walls

This paper presents experimental studies of aero-optical distortions due to a turbulent boundary layer over a range of subsonic speeds with the underlying wall both heated above and cooled below the adiabatic wall temperature. A statistical scaling model, based on Extended Strong Reynolds Analogy is derived and shown to correctly predict experimentally-observed results. The temperature mismatch between the flow and the wall was shown to have a profound effect on the level aero-optical aberrations, as the heated wall amplifies them and the cooled wall significantly reduces distortions. The importance of an inclusion of the pressure term in explaining the boundary-layer density fluctuations with the cooled wall is also discussed.