Late-time growth rate, mixing, and anisotropy in the multimode narrowband Richtmyer–Meshkov instability: The θ-group collaboration
Late-time growth rate, mixing, and anisotropy in the multimode narrowband Richtmyer–Meshkov instability: The θ-group collaboration
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DOI：
10.1063/1.4993464
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发表时间：
2017-06
影响因子：
4.6
通讯作者：
B. Thornber;J. Griffond;O. Poujade;N. Attal;H. Varshochi;Pedram Bigdelou;P. Ramaprabhu;B. Olson
中科院分区：
文献类型：
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作者：
B. Thornber;J. Griffond;O. Poujade;N. Attal;H. Varshochi;Pedram Bigdelou;P. Ramaprabhu;B. Olson
通过8个独立程序对两个初始条件进行了一系列高分辨率三维数值模拟，研究了湍流Richtmyer-Meshkov不稳定性(RMI)。模拟是用窄带微扰来初始化的，使得不稳定性增长是由于来自能量模的非线性耦合/后向散射，从而从纯RMI产生最低的预期增长率。通过独立评估每个算法的结果并计算多个算法的集合平均值，结果允许量化关键的流动特性以及由于不同的数值方法而引起的不确定性。提出了一种新的预测多模窄带扰动初始层生长的解析模型，以及线性和非线性相结合的两种模型。总体而言，生长速率指数为θ=0.292±0.009，与前人的研究结果一致，但该指数随时间缓慢衰减。此外，θ也被证明是相对独立的。
Turbulent Richtmyer–Meshkov instability (RMI) is investigated through a series of high resolution three-dimensional simulations of two initial conditions with eight independent codes. The simulations are initialised with a narrowband perturbation such that instability growth is due to non-linear coupling/backscatter from the energetic modes, thus generating the lowest expected growth rate from a pure RMI. By independently assessing the results from each algorithm and computing ensemble averages of multiple algorithms, the results allow a quantification of key flow properties as well as the uncertainty due to differing numerical approaches. A new analytical model predicting the initial layer growth for a multimode narrowband perturbation is presented, along with two models for the linear and non-linear regimes combined. Overall, the growth rate exponent is determined as θ=0.292±0.009, in good agreement with prior studies; however, the exponent is decaying slowly in time. Also, θ is shown to be relatively i...