Analysis of unsteady hypersonic shock boundary layer interactions

A shock dominated separated laminar hypersonic flow over a double cone geometry was investigated by analyzing unsteady direct simulation Monte Carlo signals with the residuals algorithm for a unit Reynolds number of 3.74×10⁵ m⁻¹ at a Mach number of 16. To investigate the origin of the striations in the bow shock observed in the amplitude functions, the momentum density was decoupled into thermal and acoustic parts using Doak's momentum potential theory. The spatial distribution of the acoustic and thermal fields shows alternating patterns, especially in the vicinity of the separation zone and the triple point. The thermal component of the momentum density was found to be large at the cone shoulder at later times due to a Kelvin-Helmholtz instability.