超重力场下球形炸药水下爆炸实验及数值模拟

常重力条件下,Mach数和Froude数无法同时满足相似。采用离心模型实验,研究水下爆炸冲击波特性及气泡脉动规律,并采用数值模拟方法重现了超重力场下的水下爆炸过程。实验及数值模拟的结果表明,重力的改变基本不影响冲击波的峰值,COLE理论在超重力环境下仍然适用,而超重力场下,小当量炸药可以模拟气泡的脉动迁移过程,其结果可以用于预测大当量炸药深水爆炸的特性。此外,为减少计算时间并提高计算精度,采用将二维冲击波作为初始条件映射到三维模型的建模方法。对于冲击波计算,网格尺寸宜取药包半径的1/20¹/10;对于气泡脉动,宜取药包半径的1/21/10;对于气泡脉动,宜取药包半径的1/2¹。

Underwater explosion experiment and numerical simulation of spherical explosives under hypergravity field

Mach and Froude numbers cannot satisfy the similar criteria simultaneously under normal gravity.Underwater explosion shock wave characteristics and bubble pulsating rule were studied by centrifugal model experiment.Similar procedure was also reproduced by numerical simulation.The results of experiments and numerical simulations showed that variation of gravity field didn't influence the peak pressure of shock wave,and it suggested the empirical formula of COLE was still valid in hypergravity field condition.Under the high gravity field,small equivalent explosives could well simulate the pulsating migration process of the bubbles,and the results could be used to predict the characteristics of the deep-water explosion of large equivalent explosives.In order to reduce the calculation time and improve calculation accuracy,numerical simulation method based on2-dimensional shock wave as initial condition was remapped into 3-dimensional model.The mesh size should be 1/201。Mach and Froude numbers cannot satisfy the similar criteria simultaneously under normal gravity.Underwater explosion shock wave characteristics and bubble pulsating rule were studied by centrifugal model experiment.Similar procedure was also reproduced by numerical simulation.The results of experiments and numerical simulations showed that variation of gravity field didn't influence the peak pressure of shock wave,and it suggested the empirical formula of COLE was still valid in hypergravity field condition.Under the high gravity field,small equivalent explosives could well simulate the pulsating migration process of the bubbles,and the results could be used to predict the characteristics of the deep-water explosion of large equivalent explosives.In order to reduce the calculation time and improve calculation accuracy,numerical simulation method based on2-dimensional shock wave as initial condition was remapped into 3-dimensional model.The mesh size should be 1/20¹/10 of the explosive radius in 2-dimensional model for shock wave calculation.The mesh size should be 1/21/10 of the explosive radius in 2-dimensional model for shock wave calculation.The mesh size should be 1/2¹of the charge radius in3-dimensional model for bubble pulsating simulation.