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 super-knock 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-planar 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 delaytime, potentially leading to detonation onset.

Refraction of a triple-shock configuration at planar fast–slow gas interfaces

“…Subsequently, understanding the underlying flow physics governing these shock refraction phenomena and their impacts on interface evolution has been a longstanding research focus. By utilizing a combination of theoretical analysis (Henderson 1966(Henderson , 1989(Henderson , 2014, experimental investigations (Abd-El-Fattah, Henderson & Lozzi 1976;Abd-El-Fattah & Henderson 1978a,b;Zhai et al 2017) and numerical simulations (Nourgaliev et al 2005;de Gouvello et al 2021), the three dominant factors determining the pattern of shock refraction have been identified. These factors include the acoustic impedances of the fluids on either side of the interface, the angle of incidence of the shock wave onto the interface, and the strength of the incident shock (Nourgaliev et al 2005).…”

“…These factors include the acoustic impedances of the fluids on either side of the interface, the angle of incidence of the shock wave onto the interface, and the strength of the incident shock (Nourgaliev et al 2005). Also, a theoretical shock refraction regime diagram taking these factors into account has been established by shock polar analysis (Abd-El-Fattah & Henderson 1978a,b;de Gouvello et al 2021). While the aforementioned studies primarily focused on gaseous interfaces, investigations of shock refraction have been extended to more complex regimes involving solid materials (Brown & Ravichandran 2014), liquids (Wan et al 2017;) and plasmas (Li, Samtaney & Wheatley 2018;Pellone et al 2021).…”

“…2005; Xiang & Wang 2019; de Gouvello et al. 2021), the three dominant factors determining the pattern of shock refraction have been identified. These factors include the acoustic impedances of the fluids on either side of the interface, the angle of incidence of the shock wave onto the interface, and the strength of the incident shock (Nourgaliev et al.…”

“…Also, a theoretical shock refraction regime diagram taking these factors into account has been established by shock polar analysis (Abd-El-Fattah & Henderson 1978 a , b ; de Gouvello et al. 2021). While the aforementioned studies primarily focused on gaseous interfaces, investigations of shock refraction have been extended to more complex regimes involving solid materials (Brown & Ravichandran 2014), liquids (Wan et al.…”