Characterization of Supersonic Wind Tunnel Flow Quality Using Planar Laser CO2 Rayleigh Scattering

A complementary experimental and computational investigation of the flow characteristics in a supersonic wind tunnel are presented. Stereoscopic planar laser Rayleigh scattering of CO2 particles, typically several nanometers to tens of nanometers in size, were used in this study allowing cross-sectional visualization of the supersonic flow and turbulent boundary layers throughout the test section of an academic scale facility. The optical diagnostic measurements show asymmetric boundary layer growth between the top and bottom walls of the test section as well as a disturbed bottom boundary layer due to the induced pressure and velocity gradient. The computational fluid dynamics simulations were used to provide additional detail and insight into the mechanisms driving these features.