水下爆炸近场非均熵流的特征线差分解法

提出了一种改进的特征线差分方法,根据力学基本方程推导出2族带有熵变修正项的特征线方程,并将质点迹线方程补充为第3族特征线方程,利用这3个特征线方程可以对水下爆炸冲击波及波后的非均熵流场进行求解。由于特征线差分法无需引入人工粘性项处理冲击波间断问题,所以减少了人为干预的影响因素。最后,应用这种改进的特征线法对质量分数比w(TNT)∶w(RDX)=40∶60的TNT/RDX炸药球的水下爆炸问题进行了数值模拟。在比例距离1R/R04的近场范围内,计算得到的冲击波峰值压力与文献实验数据的最大相对误差在13.1%以内,进一步证明了这种改进的特征线差分方法的正确性。

Difference method of characteristics in isentropic flow of underwater explosion in near-field region

Animproveddifferencemethodofcharacteristicsisdiscribed.Twogroupsofcharacteristicequationswithentropytermsarededucedaccordingtothebasicmechanicsequations,andtheparticlepathlineisaddedintheequationsetasthethirdcharacteristicequation.Theisentropicflowafterblastshockwavecanbesolvedusingthethreecharacteristicequations.Thereisnoartificialviscositytermintheequations,sotheinfluenceofthehumaninterventionisreduced.Then,byapplyingtheimproveddifferencemethodofcharacteristics,theunderwaterexplosionofthesphericalchargeofcompositionB-3isstimulated.Inthescaleddistanceof1≤R/R0≤4,thepeakpressureerrorbetweenthenumericalcalculationresultsandtheexperimentcurveislessthan13.1%,whichprovesthattheimproveddifferencemethodofcharacteristicsisreasonable.