Evolution of mixing width induced by general Rayleigh-Taylor instability
Evolution of mixing width induced by general Rayleigh-Taylor instability
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一般瑞利-泰勒不稳定性引起的混合宽度的演变
DOI：
10.1103/physreve.93.063102
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发表时间：
2016
影响因子：
2.4
通讯作者：
Tian Bao-lin
中科院分区：
文献类型：
--
作者：
Zhang You-sheng;He Zhi-wei;Gao Fu-jie;Li Xin-liang;Tian Bao-lin
由瑞利-泰勒（RT）不稳定性引起的湍流混合现象在许多自然现象和工程应用中普遍存在。混合区混合宽度是描述混合过程的最简单、最主要的参数，其变化规律对流动起着重要的作用。流动通常涉及复杂的变化的加速度历史和广泛变化的密度比，两个主要因素影响的混合宽度的演变。然而，还没有令人满意的理论预测的演变。在这里，建立了一个确定一般RT流中混合宽度演变的理论，以再现，首先，对不同的（即，恒定、脉冲、振荡、减少、增加和复杂）加速度历史和所有密度比。该理论是建立在守恒原理，特别考虑到在实际流动中发生的体积平均密度场的不对称性。结果揭示了邻近轻或重流体的混合前沿演化对不对称程度的敏感性或不敏感性，从而解释了两个实验中具有相同配置的不同演化。
Turbulent mixing induced by Rayleigh-Taylor (RT) instability occurs ubiquitously in many natural phenomena and engineering applications. As the simplest and primary descriptor of the mixing process, the evolution of mixing width of the mixing zone plays a notable role in the flows. The flows generally involve complex varying acceleration histories and widely varying density ratios, two dominant factors affecting the evolution of mixing width. However, no satisfactory theory for predicting the evolution has yet been established. Here a theory determining the evolution of mixing width in general RT flows is established to reproduce, first, all of the documented experiments conducted for diverse (i.e., constant, impulsive, oscillating, decreasing, increasing, and complex) acceleration histories and all density ratios. The theory is established in terms of the conservation principle, with special consideration given to the asymmetry of the volume-averaged density fields occurring in actual flows. The results reveal the sensitivity or insensitivity of the evolution of a mixing front of a neighboring light or heavy fluid to the degree of asymmetry and thus explain the distinct evolutions in two experiments with the same configurations.