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为解决高温高压下物质黏性的测量问题,Sakharov曾提出一种冲击波小扰动实验方法,但人们一直未从理论上给出这类特定冲击波流场中扰动振幅衰减特性与黏性系数之间的量化关联.本文首次针对Mineev等的实验条件采用数值解方法定量地研究了金属铝(Al)中复杂流场演化过程、正弦形波阵面上相对扰动幅度的演化特征和它们的黏性效应,给出了相对扰动幅度衰减曲线的零点相对距离与黏性系数之间的定量关系.与Zaidel的均匀流场模型以及Miller等的非均匀流场模型相比,本文求解的流场演变问题已经接近实验的真实情况.利用本文数值解建立起来的实验数据分析方法,Sakharov小扰动方法可以给出更为可信的黏性系数测量结果.本文重新分析了Mineev等的实验数据,发现Al在31GPa冲击压力和2×106s-1应变率条件下等效黏性系数值应修正为1100Pa·s,仅为原实验分析结果的二分之一.
In order to solve the measurement problem of material viscosity under high temperature and high pressure, Sakharov proposed a small experiment method of shock wave. However, it has never been possible to theoretically give the relationship between the amplitude attenuation characteristic and the viscosity coefficient of perturbation in this specific shock wave field Quantitative correlation.Firstly, the numerical solution method is used to quantitatively study the evolution process of complex flow field in aluminum (Al), the evolution characteristics of relative disturbance amplitude on sine wave front and their viscous effect for Mineev experimental conditions, The quantitative relationship between the relative zero-point distance and the viscous coefficient of the decay curve of relative disturbance amplitude is given. Compared with the uniform flow field model of Zaidel and the non-uniform flow field model of Miller et al., The flow field evolution problem solved in this paper is close The real situation of the experiment.Using the experimental data analysis method established by the numerical solution of this paper, Sakharov small perturbation method can give more credible viscosity coefficient measurement results.This paper re-analyzed the Mineev experimental data and found that Al in the 31GPa impact Under the conditions of pressure and strain rate of 2 × 106s-1, the equivalent viscosity value should be corrected to 1,100 Pa · s, only the half of the original experimental analysis .