浅水爆炸特性数值模拟研究

Numerical simulation of characters of shallow water explosion

为对浅水爆炸的荷载特性进行研究,首先采用LS-DYNA建立的浅水爆炸三维数值模拟模型对浅水爆炸的冲击波传播与气泡脉动进行了模拟,通过与经验计算公式对比验证了模型的可信性;然后,对浅水爆炸的荷载特点和分布规律进行了分析,并初步探究了水面及水底的影响规律,得到如下结论:LS-DYNA可实现浅水爆炸的有效模拟,模拟结果符合理论形态,且计算得到的荷载峰压和比冲量等特性参数与经验公式吻合良好。浅水爆炸荷载峰压在冲击波传播阶段出现,气泡脉动阶段荷载的比冲量则明显高于冲击波传播阶段,在浅水爆炸毁伤效应研究中,以上两个阶段均需考虑。炸药起爆深度附近及其以下水域为浅水爆炸荷载的主要作用区域。水面反射稀疏波和水底反射冲击波的峰压和衰减时间与冲击波相近;随着爆深增加,反射波对水面及水底附近位置影响增大,对水域中间位置的影响先减小后增大。

In order to study the characters of shallow water explosion,this paper implements the LSDYNA to generate a three-dimensional numerical simulation model of shallow water explosion,and simulates the bubble pulsation and propagation of impact wave caused by shallow water explosion.By validating the creditability of the model through comparing simulation results with the formula of empirical formula,and by analyzing the load characteristic and distribution of underwater explosive,this paper develops the following conclusions：LS-DYNA is able to simulate the shallow water explosion effectively,and the simulation results matches with the theory,and the calculated characteristic parameters such as peak load pressure and specific impulse tally with the experience formula relatively well.The pressure caused by shallow water explosion is mainly generated at the phase of impact wave propagation and first bubble pulsation.During the process of shallow water explosion,the peak pressure is generated at the phase of impact wave propagation,however,the specific impulse of the bubble pulsation pressure is significantly higher than the impact wave pressure,and both phases need to be considered.The primary effect area of explosion pressure should be the surrounding area of explosion and area below.The peak pressure and decay time of reflected shock wave are close to those of shock wave.With the increase of explosion depth,the influence of reflected wave increases in position of water surface and bottom,and the influence decreases first and then increases in position of middle water.