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Abstract. We applied spontaneous Rayleigh-Brillouin scattering for measuring kinetic coefficients and velocity of flows. A kinetic model was used for spectral line shape calculation in case of wide aperture Fabri-Perot spectrometer. The calculation well corresponds to experimental spectra for stationary nitrogen and atmospheric air flow up to 3 Mach number. IntroductionLaser Rayleigh-Brillouin scattering is useful tool for diagnostics of gases [1,2]. Scattered signal has spectral features reflecting the pressure, temperature and internal energy states of the gas. The method achieves high precision with using narrowband continuous wave lasers and thermostatic gas cell. Long collection of scattered radiation gives low level noise/signal ratio. Some kinetic models [3-5] predict spectral line shapes and define pressure macroscopic transport coefficients, such as the shear viscosity, the heat conductivity. The last S6 Tenti model [5] allows defining bulk viscosity, but also needs new approach for gas mixtures. In the work we used previous kinetic model [3] and applied it for interpreting of supersonic gas flows. Instability of real flows requires a short-time registration of spectrum and wide aperture.

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