水下爆炸冲击波数值仿真研究

由于在水下爆炸冲击波的数值仿真研究中,水的状态方程、人工黏性系数和网格尺寸对数值计算结果影响很大,采用常规TNT炸药的水下爆炸为例,以冲击波的峰值压力和比冲量为衡量指标,研究了这3个主要影响因素对数值仿真结果的影响。首先,通过采用常用的5种水的状态方程进行系列仿真,给出了各种状态方程的适用范围;其次,讨论了人工黏性系数对计算结果的影响,并给出了一次与二次人工黏性系数的建议取值范围;最后,通过对不同炸药当量及不同网格尺寸开展系列运算,从而得到不同炸药当量在满足工程计算精度要求下所对应的建议网格尺寸,并得到了不同炸药当量所对应的建议网格尺寸的表达式。

Shock Wave Simulation of Underwater Explosion

The state equation of water,artificial viscosity coefficient and mesh size have a great influence on the numerical results of underwater explosion shock wave.In order to improve the simulation accuracy of underwater explosion shock wave,the peak pressure and specific impulse of the conventional TNT explosive underwater explosion are taken as the measurement indicators,and the influence of these factors on the numerical simulation results is studied.For the five kinds commonly state equations of water,the specific values of the artificial viscosity coefficients under different working conditions and appropriate grid size for different explosive equivalents are given.These parameters can provide reference for improving simulation accuracy of underwater explosion shock wave under different working conditions.First,through a series of simulations of the commonly used five kinds of state equations of water,the calculation results of peak pressure and specific impulse are compared with the empirical formula,and the error analysis is carried out to give the applicable scope of each state equation.Secondly,the influence of the artificial viscosity coefficient on the calculation results is discussed,and a series of calculations are carried out for the primary and secondary artificial viscosity coefficients under different working conditions.The recommended range of values for the primary and secondary artificial viscosity coefficients under different working conditions is given.Finally,through a series of calculations on 0.1,0.5,1,10,50,100,500 and 1000 kg equivalent explosives and different grid sizes,the recommended mesh sizes corresponding to different explosive equivalents under the requirement of engineering calculation accuracy are obtained by limiting the relative error of peak pressure less than 10%.The expressions of the recommended mesh sizes corresponding to different explosive equivalents are also given.