基于SPH方法的浅水爆炸研究

Research on shallow water explosion based on SPH method

通过SPH方法,利用Fortran编程,首先对自由场中装药爆炸进行模拟,将结果与经验公式对比,验证Fortran程序的有效性和正确性。然后对浅水爆炸问题进行数值模拟,再现浅水爆炸的基本物理现象,研究浅水爆炸相对于无限水域爆炸所独有的压力和冲量特性;通过对浅水爆炸不同参数的研究,给出了不同爆深对压力和冲量的影响,分析水底泥沙密度对冲击波压力的影响,给出不同泥沙密度下浅水中压力的变化规律。研究表明,浅水爆炸同时受到水面和水底的作用,水面效应使压力曲线产生截断效应,底部效应会增加压力脉宽。随着爆深的增大,压力曲线逐渐由削弱峰值、削弱脉宽过渡为增大峰值、增大脉宽,冲量逐渐增大,水冢逐渐减小;随着泥沙密度的增加,浅水中压力峰值增大,作用脉宽也增大,直达波、水面反射波以及水底反射波的相互作用更加明显。本文研究旨在揭示上述问题的作用机理,总结规律性结论,为舰船水下爆炸结构响应预报和舰船结构的防护设计提供参考。

The explosion of under water was simulated numerically with Fortran programming model by SPH method. First, explosion of free field is simulated which was compared with experience formula to verify the correctness and effectiveness of Fortran program. Then the basic physical phenomenon was reproduced and their unique pressure and impulse characteristics compared with infinite water were studied. Then by changing different parameters, the influence on pressure and impulse with various explosion depth was studied. The influence on pressure with various bottom sediment density was analyzed and the law of pressure was given. Study shows that, explosion of shallow water is affected by both water surface and sediment bottom. The surface effects lead to truncation effect in pressure curve and the bottom effects increase the pressure pulse width. With the explosion depth increases, the pressure curve gradually transfer from weakening peak, weakening pulse width to increase peak width, increase impulse and water mound decrease. With the increase of sediment density, peak pressure and pulse width of shallow water all increase, and interactions among direct wave, surface reflected wave and bottom reflected wave become more pronounced. This paper aims at revealing mechanism of action and summarizes regular conclusion to provide reference for ship structural response of underwear explosion forecast and ship protect structure designing.