A new idea to predict reshocked Richtmyer-Meshkov mixing: constrained large-eddy simulation
A new idea to predict reshocked Richtmyer-Meshkov mixing: constrained large-eddy simulation
复制标题
预测再激 Richtmyer-Meshkov 混合的新思路：约束大涡模拟
DOI：
10.1017/jfm.2021.332
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发表时间：
2021
影响因子：
3.7
通讯作者：
Chen Shiyi
中科院分区：
文献类型：
--
作者：
Bin Yuanwei;Xiao Mengjuan;Shi Yipeng;Zhang Yousheng;Chen Shiyi
两种介质的湍流Richtmyer-Meshkov（RM）混合是由界面不稳定性引起的更普遍、更复杂的湍流混合中最具代表性的问题，广泛存在于自然界和工程应用中。准确预测其空间结构和混合宽度的演变具有重要意义。然而，满意的预测与大涡模拟（LES）尚未实现，即使是最重要的MW。在本文中，我们创造性地解决这个问题，结合约束大涡模拟（克莱斯）的想法，以前只成功地在经典的单介质湍流，我们最近开发的雷诺平均Navier-Stokes（RANS）模型，实现了令人满意的预测MW。具体地说，在我们目前开发的克莱斯模型中，借助于Reynolds分解，非闭合亚网格尺度（SGS）LES模型被分解为两个部分，即平均和脉动。平均的部分占主导地位，我们最近开发的RANS模型，以准确地预测MW的对应建模，而波动的部分与经典的Smagorinsky模型建模。因此，除了成功地捕捉三维大尺度结构的湍流和（归一化）混合质量的演变，我们新提出的克莱斯也预测一个令人满意的MW与一个非常粗糙的网格。据我们所知，这是LES第一次可以产生与实验相当的结果。
The reshocked turbulent Richtmyer–Meshkov (RM) mixing of two media is the most representative problem of more general and complex turbulent mixing induced by interfacial instabilities, broadly occurring in both nature and engineering applications. An accurate prediction of its evolving of spatial structure and mixing width (MW) is of fundamental importance. However, satisfactory prediction with the large-eddy simulation (LES) has not yet been achieved, even for the most important MW. In this paper, we innovatively solve this problem by combining the idea of the constrained large-eddy simulation (CLES), which succeeded previously only in classical single-medium turbulence, and our recently developed Reynolds averaged Navier–Stokes (RANS) model, which realized a satisfactory prediction of MW. Specifically, in our currently developed CLES model, with the aid of Reynolds decomposition, the unclosed subgrid scale (SGS) LES model is decomposed into two parts, i.e. the averaged and the fluctuating. The averaged part is dominated and modelled by the counterpart of our recently developed RANS model to accurately predict the MW, while the fluctuating part is modelled with the classical Smagorinsky model. Consequently, besides successfully capturing the three-dimensional large-scale structure of turbulence and the evolution of the (normalized) mixed mass, our newly proposed CLES also predicts a satisfactory MW with a very coarse grid. To the best of our knowledge, this is the first time that the LES can yield such a comparable result with experiment.