Molecular Rayleigh Scattering to Measure Velocity and Temperature in High-speed Wind Tunnels

We have been developing a spectrally resolved, molecular Rayleigh technique where a CW laser beam is
passed through the high-speed flow and light scattered by the gas molecules of air are collected from points on the laser path. The light is spectrally resolved to determine the Doppler shift (for velocity) and thermal broadening (for temperature) from the gas flow. We have demonstrated the technique in supersonic jets and now working to implement in a high-speed wind tunnel.