Numerical simulations of trajectories of shock wave triple points in near-ground explosions of TNT charges

Abstract

To accurately predict the locations and trajectories of shock wave triple points in near-ground explosions, this study determined the propagation law of shock waves after the initiation of a detonator using a schlieren system. Moreover, it established a numerical simulation model using the Autodyn software and verified the accuracy of the model through a detonator explosion experiment. The propagation law of shock waves of TNT charges (1, 10 ​kg and 100 ​kg) at different heights of burst(0.5, 1.0, 1.5, 2.0 ​m,and 2.5 ​m) was studied through numerical simulations, and the triple point trajectories were fitted to an empirical formula. The results show that the maximum simulation error relative to the schlieren images of detonator explosions did not exceed 4 ​mm. As the scaled height of burst decreased, the positions of generated triple points were closer to the vertical projection of the explosion center and rose faster. As the scaled distance increased, the scaled height of triple points rose exponentially. The average error of triple point trajectories between the values predicted in this study and the experimental values was 4.1%, indicating that the accuracy of the fitted formula is acceptable. This study revealed the overpressure distribution law of shock waves and will provide a reference for shock wave overpressure measurements and explosion protection.

Keywords

• Shock wave
• Mach reflection
• Triple point
• Numerical simulation
• TNT charge