Coherent Anti-Stokes Raman Scattering Measurements and Computational Modeling of Nonequilibrium Flow

An experimental study is conducted in a high-enthalpy continuous facility to investigate the nonequilibrium shock-layer airflow induced by a two-dimensional body. The rotational and vibrational temperatures of nitrogen as well as the number density are measured by recording the rovibrational spectra of molecular nitrogen using coherent anti-Stokes Raman scattering spectroscopy. Measurements are performed in the freestream and within the shock layer induced by a disk model. Difficulties specific to the application of an optical technique to a high enthalpy flow are discussed, and flows parameters are given. The nozzle and shock-layer flows are modeled numerically using a nonequilibrium Navier-Stokes solver. Good agreement is achieved between the experimental and calculated results.