水下爆炸冲击波数值模拟的网格尺寸确定方法

网格尺寸对水下爆炸冲击波传播过程的数值模拟精度有较大影响,且不同当量下可接受的网格尺寸也有较大区别。通过研究不同比例爆炸距离处水下爆炸冲击波峰值、比冲量对有限元网格尺寸的依赖性,以"炸药半径与网格尺寸之比"作为网格尺寸划分依据,提出了一种对不同当量均具有较强适用性的网格尺寸确定方法;对数值结果的误差分析表明,采用炸药半径的1/3作为数值模型的网格尺寸,其计算精度可满足工程要求;同时通过对数值计算误差进行非线性拟合,得到了不同网格尺寸下冲击波峰值压力、比冲量的误差估计式,可为研究人员根据可接受的误差范围确定任意当量下合适的网格尺寸或估计数值计算的整体误差提供参考。

A method for determining mesh size in numerical simulation of shock wave from underwater explosion

The numerical simulation accuracy of underwater explosion shock wave propagation well depends on the mesh size, and the acceptable mesh size varies with the charge weight. Through analyzing the mesh size effect at different scaled distances of shock wave peak pressure and impulse, with the explosive radius and the grid size ratio as a criterion for determining mesh size, a mesh size determining method which is suitable for various charge weights was proposed. And according to the error analysis of numerical results, if taking one third of the explosive radius as the mesh size, the numerical accuracy can meet the requirements of engineering. In addition, through nonlinear fitting of numerical simulation errors, the error estimation formulas of peak pressure and impulse were put forward. These error estimation formulas can play a strong guiding role for researchers in selecting an appropriate mesh size according to the charge weight and the acceptable error range or estimating the accuracy of numerical results.