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1≤R/R0≤4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.%An improved difference method of characteristics is discribed. Two groups rrnof characteristic equations with entropy terms are deduced according to rrnthe basic mechanics equations, and the particle path line is added in the rrnequation set as the third characteristic equation. The isentropic flow rrnafter blast shock wave can be solved using the three characteristic rrnequations. There is no artificial viscosity term in the equations, so the rrninfluence of the human intervention is reduced. Then, by applying the rrnimproved difference method of characteristics, the underwater explosion of rrnthe spherical charge of composition B-3 is stimulated. In the scaled rrndistance of 1≤R/RO≤A, the peak pressure error between the numerical rrncalculation results and the experiment curve is less than 13. 1%, which rrnproves that the improved difference method of characteristics is rrnreasonable.
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