Irregular configurations of shock wave impingement on shear layers*

This work examines the interaction of a shear layer separating two uniform supersonic streams of Mach numbers M₁ and M₂ with an oblique shock approaching at an incident angle σ_i. The development considers the outer problem of oblique–shock impingement on a supersonic vortex sheet of infinitesimal thickness, for which the region of existence of regular shock refractions with downstream supersonic flow is delineated in the parametric space (M₁, M₂, σ_i). Neumann-Henderson plots are employed to characterize the family of solutions involving regular and non-regular configurations. Theoretical tools and high-fidelity DNS are employed to resolve the evolution of the complex structures present in the flow. The massively-parallel finite-difference code CREAMS is being used to solve the unsteady, two-dimensional set of compressible Euler equations for multicomponent gas mixtures.  The code accurately reproduces the expected regular interactions and provides the evolution of non-regular unstable configurations.