水下爆炸冲击波数值模拟的网格尺寸确定方法

摘要

The numerical simulation accuracy of underwater explosion shock wave propagation depends on mesh size,and the acceptable mesh size varies with charge weight.Through analyzing the mesh size effect on different scaled distances of shock wave peak pressure and impulse,taking the ratio of explosive radius to grid size as a criterion to determine mesh size,a mesh size-determining method being suitable for various charge weights was proposed.The error analysis of numerical results showed that 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 for peak pressure and impulse of shock wave under different mesh sizes are derived.These error estimation formulas provided a reference for researchers to select an appropriate mesh size according to the charge weight and the acceptable error range or to estimate the accuracy of numerical results.%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。