The development of secondary instability on streamwise vortex structures generated
in a hypersonic shock layer on a flat plate is experimentally studied for the flow
with Mach number M∞ = 21 and unit Reynolds number
Re1 = 6 × 105 m−1. The
study is performed using the electron-beam method. The generation of weak unsteady
vortices and steady streamwise vortex structures with finite-amplitude perturbations
imposed onto them is studied in detail. Complex data on the characteristics of density
fluctuations developed on quasi-steady and unsteady streamwise vortex structures are
obtained. It is shown that the characteristics of the natural fluctuations of density
developing in the shock layer on a flat plate are qualitatively similar to density
fluctuations induced by weak unsteady vortex perturbations introduced into the shock
layer. The possibility of existence of parametric resonance between the fundamental
frequency and its harmonic and between harmonics for steady streamwise vortex
structure is shown.
Self-Consistent Simulation of the Electric Field in a Rarefied Hypersonic Shock Layer
