Effect of Activation Energy on Detonation Cellular Dynamics and Reinitiation Behaviors

Two-dimensional simulations of detonation propagation in a channel filled with stoichiometric hydrogen–air mixture with unity Lewis number using the chemical-diffusive model (CDM) coupled with compressible Navier–Stokes equations are presented. Specifically, the effect of four activation energies ([Formula: see text], and 10) with CDM on detonation cell structures, cellular dynamics, and reinitiation behaviors is discussed. As [Formula: see text] increases, detonation cell size increases and the cellular structure becomes more irregular. Spectral analysis by the auto-correlation function is performed to provide quantitative insights about detonation cell size and irregularity. Furthermore, detailed analysis on the detonation wavefront captures three distinct detonation propagation modes, including stable detonation ([Formula: see text]), weakly unstable detonation ([Formula: see text]), and highly unstable detonation ([Formula: see text]). The effect of activation energy in detonation attenuation is further studied through a detonation propagation over a semicylinder obstacle, where two distinct detonation attenuation regimes are captured, including unattenuated detonation transmission ([Formula: see text]) and critical detonation reinitiation ([Formula: see text]). The mechanism of the critical detonation reinitiation event is further examined. It is found that a strong transverse detonation wave forms at higher activation energies after the Mach shock reflection at the bottom wall, which eventually leads to a steady detonation propagation.