Discrete Boltzmann modeling of Rayleigh-Taylor instability in two-component compressible flows
Discrete Boltzmann modeling of Rayleigh-Taylor instability in two-component compressible flows
复制标题
二分量可压缩流中瑞利-泰勒不稳定性的离散玻尔兹曼建模
DOI：
10.1103/physreve.96.053305
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发表时间：
2017-11-13
影响因子：
2.4
通讯作者：
Li, Yingjun
中科院分区：
文献类型：
--
作者：
Lin, Chuandong;Xu, Aiguo;Li, Yingjun
本文提出了一种离散Boltzmann模型（DBM）来研究二组分可压缩流动中的Rayleigh-Taylor不稳定性（RTI）。每个物种都有一个灵活的比热比，并由一个离散的玻尔兹曼方程（DBE）描述。两个DBE采用独立的离散速度。DBE中的碰撞项和力项分别说明了分子碰撞和外力。利用两种类型的力项。除了恢复流体动力学极限下的修正Navier-Stokes方程外，DBM还具有捕获详细非平衡效应的能力。此外，我们使用DBM来研究RTI的动态过程。提出并研究了非平衡效应张量的不变量。对于低雷诺数，全球非平衡表现和混合熵的增长率都显示出三个阶段（即，减少，增加，然后减少的趋势）。另一方面，早期减少的趋势被抑制，甚至消除高雷诺数。并对相关的物理机制进行了分析和讨论。
A discrete Boltzmann model (DBM) is proposed to probe the Rayleigh-Taylor instability (RTI) in two-component compressible flows. Each species has a flexible specific-heat ratio and is described by one discrete Boltzmann equation (DBE). Independent discrete velocities are adopted for the two DBEs. The collision and force terms in the DBE account for the molecular collision and external force, respectively. Two types of force terms are exploited. In addition to recovering the modified Navier-Stokes equations in the hydrodynamic limit, the DBM has the capability of capturing detailed nonequilibrium effects. Furthermore, we use the DBM to investigate the dynamic process of the RTI. The invariants of tensors for nonequilibrium effects are presented and studied. For low Reynolds numbers, both global nonequilibrium manifestations and the growth rate of the entropy of mixing show three stages (i.e., the reducing, increasing, and then decreasing trends) in the evolution of the RTI. On the other hand, the early reducing tendency is suppressed and even eliminated for high Reynolds numbers. Relevant physical mechanisms are analyzed and discussed.