Numerical simulation for Mach reflection in air explosion near ground

In order to study variation law of Mach wave's parameters and effects of charge type and charge shape on triple-point trajectory, the finite element analysis software AUTODYN was adopted here to establish a finite element model of TNT charge in air explosion near ground. The calculated results were compared with test ones, and the former agreed well with the latter. Then, numerical simulations were performed for near-ground air explosions with different charge shapes and charge types. The results showed that impulse on Mach wave front surface decreases slowly with increase in height, overpressure peak value firstly decreases slowly with increase in height and then decreases rapidly; Mach wave is approximately perpendicular to ground, overpressure peak value at its top is only 67.6%-80.3% of that at its bottom, and impulse at its top is 91.3%-99.0% of that at its bottom; triple-point trajectory of spherical charge and that of column one with a length to diameter ratio of 1 are almost identical; the larger the length to diameter ratio of column charge, the smaller the height of Mach wave; Mach wave height formed with C4 explosive is slightly larger than that with B explosive, but they are relatively close to each other; Mach wave height formed with TNT is obviously smaller than those with C4 and B explosives © 2020, Editorial Office of Journal of Vibration and Shock. All right reserved.