近地面空中爆炸马赫反射数值模拟研究

为研究马赫波冲击波参数的变化规律以及装药类型和装药形状对三波点迹线的影响,采用有限元分析软件AUTODYN建立了TNT装药近地面空中爆炸的有限元模型,将计算结果与试验结果进行了对比,两者吻合良好。在此基础上,对不同装药形状和装药类型的炸药进行了近地面空中爆炸的数值模拟。研究结果表明:马赫波波阵面上的冲量随高度增大而缓慢减小,超压峰值随高度增大先缓慢下降而后迅速减小。马赫波与地面近似垂直,其顶部的超压峰值仅为底部的67.6%~80.3%,顶部的冲量为底部的91.3%~99.0%。球形装药和长径比为1的柱状装药的三波点迹线几乎完全相同,柱状装药长径比越大,马赫波高度反而越小。C4炸药形成的马赫波高度略大于B炸药,但两者较为接近,TNT形成的马赫波高度明显小于C4和B炸药。

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