Time-dependent study of anisotropy in Rayleigh-Taylor instability induced turbulent flows with a variety of density ratios
Time-dependent study of anisotropy in Rayleigh-Taylor instability induced turbulent flows with a variety of density ratios
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DOI：
10.1063/1.5110914
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发表时间：
2017-10
影响因子：
4.6
通讯作者：
Ye Zhou;W. Cabot
中科院分区：
文献类型：
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作者：
Ye Zhou;W. Cabot
这项研究重点在于理解由瑞利 - 泰勒不稳定性所引发的流动的随时间变化的各向异性、混合以及标度，并对卡博特和周所报道的后期快照进行补充[“瑞利 - 泰勒不稳定性引发的湍流的标度和各向异性的统计测量”，《流体物理》25卷，015107（2013年）]。特别是，我们利用来自在中等雷诺数下分辨率良好的直接数值模拟的三个具有不同阿特伍德数（密度比）的大型数据集，目的是确定这种非均匀流与均匀各向同性湍流的偏离程度。为了详细描述加速度所起的作用，我们详细考虑了三个关键的随时间变化的统计测量。首先，对这种各向异性湍流中的一些方向长度尺度进行了考察。其次，也阐明了外尺度、湍流长度以及基于泰勒微尺度的雷诺数之间的关系。最后，利用归一化耗散率来考察在平行于重力的非均匀方向以及在垂直的均匀方向上流动的独特特征。这项研究重点在于理解由瑞利 - 泰勒不稳定性所引发的流动的随时间变化的各向异性、混合以及标度，并对卡博特和周所报道的后期快照进行补充[“瑞利 - 泰勒不稳定性引发的湍流的标度和各向异性的统计测量”，《流体物理》25卷，015107（2013年）]。特别是，我们利用来自在中等雷诺数下分辨率良好的直接数值模拟的三个具有不同阿特伍德数（密度比）的大型数据集，目的是确定这种非均匀流与均匀各向同性湍流的偏离程度。为了详细描述加速度所起的作用，我们详细考虑了三个关键的随时间变化的统计测量。首先，对这种各向异性湍流中的一些方向长度尺度进行了考察。其次，也阐明了外尺度、湍流长度以及基于泰勒微尺度的雷诺数之间的关系。最后，利用归一化耗散率来考察在平行于重力的非均匀方向以及在垂直的均匀方向上流动的独特特征。（最后重复部分未翻译新内容，可能是原始文本重复）
This study focuses on understanding the time-dependent anisotropy, mixing, scaling of flows induced by Rayleigh-Taylor instability, and complementing the late-time snapshots reported by Cabot and Zhou [“Statistical measurements of scaling and anisotropy of turbulent flows induced by Rayleigh-Taylor instability,” Phys. Fluids 25, 015107 (2013)]. In particular, we utilize three large datasets with different Atwood numbers (density ratios) from well resolved direct numerical simulations at a moderate Reynolds number with the goal of determining the degree of departure of this inhomogeneous flow from that of homogeneous, isotropic turbulence. Three key time-dependent statistical measurements are considered in detail to delineate the role played by the acceleration. First, a number of directional length scales in this anisotropic turbulence are inspected. Second, the relationship among the outer-scale, the turbulence length, and the Taylor-microscale based Reynolds numbers is also clarified. Finally, the normalized dissipation rate is employed to inspect the distinctive features of the flow in the inhomogeneous direction parallel to gravity and in the homogeneous perpendicular directions.This study focuses on understanding the time-dependent anisotropy, mixing, scaling of flows induced by Rayleigh-Taylor instability, and complementing the late-time snapshots reported by Cabot and Zhou [“Statistical measurements of scaling and anisotropy of turbulent flows induced by Rayleigh-Taylor instability,” Phys. Fluids 25, 015107 (2013)]. In particular, we utilize three large datasets with different Atwood numbers (density ratios) from well resolved direct numerical simulations at a moderate Reynolds number with the goal of determining the degree of departure of this inhomogeneous flow from that of homogeneous, isotropic turbulence. Three key time-dependent statistical measurements are considered in detail to delineate the role played by the acceleration. First, a number of directional length scales in this anisotropic turbulence are inspected. Second, the relationship among the outer-scale, the turbulence length, and the Taylor-microscale based Reynolds numbers is also clarified. Finally, the norma...