水下爆炸冲击过程三维数值模拟

Three-dimensional numerical simulation of underwater explosion process

为研究无限域和近水面水下爆炸冲击波压力特点以及近水面的物理特性,基于多物质ALE方法,采用ANSYS/LS-DYNA有限元分析软件,对无限域和近水面水下爆炸进行了三维数值模拟,再现了爆轰产物、水以及空气多物质介质间的相互作用过程。分析发现,在爆深不变的情况下,随着测深的减小,自由面对冲击波的影响主要体现在减小入射冲击波波形脉宽和削弱冲击波峰值压力上;相同当量炸药在自由面产生的水柱,其上升的速度随着爆深的减小而逐渐增大。定性地分析了近水面水下爆炸的密度分布情况,以及不同爆深情况下自由面水柱的形成过程。通过数值模拟研究了冲击波压力值的特性,并与经验值进行了对比,验证了计算模型具有较好的计算精度,同时三维再现了水下爆炸的复杂物理现象。

In order to study the pressure characteristics of the underwater shock wave in the infinite water and near air-water surface and the physical characteristics of the air-water surface,three-dimensional numerical simulationof infinite water and near air-water surface underwater explosion was carried out based on the arbitrary Lagrangian-Eulerianmethod by finite eldment software ANSYS/LS-DYNA.The interaction between the water and the air during the process of explosion is investigated.According to analysis,we found that in the condition of the depth of detonation remaining unchanged,the influence of air-water surface on shock wave is mainly reflected in reducing the pulse width of incident shock wave and reducing the peak pressure of shock wave with the decrease of sounding depth.The height of water column produced by the same TNT explosive on the air-water surface increases with the decrease of the detonation depth.At the same time,the density distribution near air-water surfaceand the process of water column forming under different detonation depths are qualitatively analyzed,which is also reproduced with three-dimensional numerical simulation method.With the numerical simulation method,the characteristics of the shock wave val-ues are analyzed and certify that the model has better calculation accuracy compared with the empirical formula,and the process of underwater explosion near air-water surface is also represented.