Decay behavior and internal interactions of regularly reflected spherical blast waves

Abstract

Blast wave reflection is a critical area in military and infrastructure defense, converging shock dynamics, and colliding blast waves. While irregular blast reflections have garnered remarkable attention, research on regularly reflected (RR) blast waves remains comparatively limited. This study presents a detailed literature on shortcomings of post-reflection quantities of RR blast waves and aims to bridge this gap by extensively analyzing RR behaviors of spherical blast waves against a planar surface in air via numerical methods. With 31 scenarios involving a 1 kg charge and scaled distances from 0.5 to 4.0 m/kg1/3, comprehensive field data on parameters including pressure, density, and velocity were gathered using a fan-like gauge array. A dedicated program for tracking the RR shock front was developed, enabling precise trajectory detection and detailed quantitative analyses of RR wave decay. First, accurate empirical trajectory equations for RR waves were formulated along its normal axis. Second, spatial decay analysis was conducted, revealing consistent decay rates for each RR field parameter under 1 m/kg1/3 and diminishing decay rates beyond this threshold. Third, parameter profiles preceding RR shock fronts at various post-reflection distances were examined, while discrepancies and complexities against generalized profiles were uncovered. Qualitatively, this study identified four internal interactions within the reflection phenomenon, categorized by scaled distance ranges, and elucidated the secondary wave's impact on RR wave propagation. The comprehensive quantitative and qualitative findings in this work offer profound insights into blast wave dynamics, addressing several gaps on RR blast wave behaviors and laying a foundation for understanding more complex blast reflection phenomena crucial in various domains.