Rotational temperature and density measurements in a hypersonic flow by dual-line CARS

Coherent anti-Stokes Raman scattering and spontaneous Raman scattering diagnostics of nonequilibrium plasmas and flows

“…An early work in this field is by Slenszka et al [55] who used narrowband scanning H 2 CARS in folded BoxCARS geometry for rotational temperature measurements in a free expansion of hydrogen jet exiting from an RF heated nozzle, at nozzle temperatures of T = 300-2500 K, detecting significant vibrational-rotational nonequilibrium. Grisch et al [56] used narrowband dualline N 2 CARS in folded BoxCARS geometry to measure 2D distributions of N 2 rotational temperature and number density in Mach 10 nitrogen flow, in a shock wave-boundary layer interaction region behind compression corner. Pulford et al [57] and Boyce et al [58] used single-shot broadband N 2 CARS spectra, also in folded BoxCARS geometry, for measurements of N 2 rotational and vibrational temperatures in a pulsed free piston supersonic shock tunnel flow facility, both in freestream and in a bow shock layer in front of a blunt body.…”

Hypersonic Boundary Layer Analysis - Comparison of Velocity Measurements and Monte-Carlo Calculations

“…This facility maintains stable stagnation conditions with a good reproducibility in 60s-long runs. The jet velocity was previously measured by a Pitot tube [11] whereas the density and the temperature were obtained by using the dual-line CARS technique [12]. By comparison of velocity profiles and Navier Stokes calculations, it was deduced that the Mach number is 9.9 ± 0.07.…”

Pressure, temperature, and density measurements using high-resolution N2 CARS

“…Grisch et al 12 and Péalat and Lefebvre 13 used dual-line CARS (DLCARS) to measure rotational temperature and gas density in low-pressure flows. In addition to a pump beam, dual-line CARS employs two narrowband dye lasers tuned to two rotational lines in the N 2 bandhead, forming two distinct CARS signals.…”