Extreme near-field reflected blast loads of cylindrical charges

Accurate prediction of near-field reflected blast loads is critical for structural safety assessment and protective design. However, the spatiotemporal characterization of extreme near-field blast loads remains insufficient. This study established a numerical model to investigate blast reflections from cylindrical charges, accounting for the coupled effects of detonation products and shock waves. The results reveal that the reflected blast wave follows a self-similar evolution, with the interface of detonation products transitioning from a smooth state to a complex morphology of random microjets as the expansion radius increases. With increasing scaled distance, the high-pressure region of cylindrical charges diminishes significantly due to radial rarefaction waves. At larger aspect ratios, the dynamic pressure of detonation products in the regular reflection region exceeds that of spherical charges, while the opposite trend occurs in the Mach reflection region. Furthermore, the reflected peak loads of cylindrical charges decay nonlinearly and monotonically with scaled distance, whereas the peak overpressure attenuates non-monotonically with incident angle due to Mach reflection effects. For higher aspect ratios, the overpressure amplitude in the regular reflection region increases continuously, with peak overpressure contours converging axially. Additionally, as the load amplitude decreases, the contribution area ratios of reflected peak loads between cylindrical and spherical charges gradually diminish. This study presents a quantitative investigation of extreme near-field blast load characteristics from cylindrical charges, contributing insights for predictive model development.