Wave Processes in the Hypersonic Shock Layer on a Flat Plate

An electron-beam fluorescence technique is used to investigate the properties of density waves in the shock layer on a flat plate placed in a hypersonic stream (M_x=21) at zero incidence; the Reynolds number based on the longitudinal coordinate and the freestream parameters is Re_x=(2.7–3)·10⁵. Transverse profiles of the mean density and the overall and spectral levels of the density fluctuations are obtained, the longitudinal and lateral phase velocities of the waves and the correlation scales are determined, and the longitudinal increments of the waves are derived. The data are compared with the experimental results obtained at Re_x=(2.6–7)10·⁴.