Anatomy of a diffracting detonation in a circular arc of explosive

Abstract

Using high-resolution numerical simulation, Short et al. (J. Fluid Mech. vol. 835, 2018, pp. 970–998) study diffraction of a detonation as it traverses a $270^{\circ }$ finite-thickness condensed-phase explosive arc. This geometry admits a steady solution in a frame rotating with angular speed $\unicode[STIX]{x1D714}_{0}$, which thereby facilitates a detailed analysis of how the loss of energy from the detonation reaction zone due to the diffraction process slows the propagation of the detonation. There exists a region of subsonic flow, between the detonation shock and the curve of sonic flow (labelled the DDZ), which is responsible for setting $\unicode[STIX]{x1D714}_{0}$. Although the DDZ spans the entire thickness for thin arcs, it is localized to a region near the inside surface as the arc is thickened. Thus the explosive energy release near this inside surface plays a disproportionate role in the diffraction process.