Shock wave refraction patterns at a slow–fast gas–gas interface at superknock relevant conditions

Abstract

Shock wave refraction theory and high-resolution numerical simulations were employed to predict the refraction pattern under superknock relevant conditions at slow–fast gas–gas interfaces which are characterized by a higher acoustic impedance in the incident phase than in the transmitted phase. First, our theoretical and computational methodologies were validated against results from the literature for planar shock–straight oblique interface interactions. Second, our framework was applied to planar shock-/cylindrical shock–cylindrical interface interactions. The theoretical regime diagram agrees well with the numerical predictions for the former configuration whereas significant discrepancies were observed for the latter. Numerical results show the formation of temperature and pressure peaks as the refraction structure transits from a free precursor refraction to a twin von Neumann refraction. This change in thermodynamic state can induce a significant reduction in ignition delay time, potentially leading to detonation onset.