Strong shock propagation for the finite-source circular blast in a confined domain

The circular explosion wave produced by the abrupt discharge of gas from a high-temperature heat source serves as a crucial model for addressing explosion phenomena in compressible flow. The reflection of the primary shock and its propagation within a confined domain are studied both theoretically and numerically in this research. Under the assumption of strong shock, the scaling law governing propagation of the main shock is proposed. The dimensionless frequency of reflected shock propagation is associated with the confined distance. The numerical simulation for the circular explosion problem in a confined domain is performed for validation. Under the influence of confinement, the principal shock wave systematically undergoes reflection within the domain until it weakens, leading to the non-monotonic attenuation of kinetic energy in the explosion fireball and periodic oscillations of the fireball volume with a certain frequency. The simulation results indicate that the frequency of kinetic energy attenuation and the volume oscillation of the explosive fireball align consistently with the scaling law.