Abstract Turbulent two-phase flows feature different mechanisms for production and dissipation of turbulent kinetic energy compared to the single-phase flows. However, this difference is usually neglected in developing eddy viscosity-based subgrid scale (SGS) models for the two-phase large eddy simulation (LES). In this study, a new approach is presented for the two-phase LES to include the surface tension, which is a production mechanism for the kinetic energy in the small scale motions, into the subgrid eddy viscosity model. We follow the Favre-filtered governing equations of interfacial flows based on the volume of fluid (VOF) approach and derive the transport equation for the turbulent kinetic energy to include the effect of surface tension. The original contribution of this study is to propose a new form for the eddy viscosity based on the mixing length assumption which includes an additional production mechanism of turbulent kinetic energy stemming from the interfacial work i.e. surface tension. The proposed model for eddy viscosity is employed to close all the SGS terms. The model performance is evaluated by means of the a-priori filtering of the fine grid simulation of phase inversion problem. To test the generality of the model at different physical conditions, two different density ratios were considered for the fine grid simulation. The results highlight a significant improvement of the eddy viscosity-based SGS models in prediction of the turbulent kinetic energy for the small unresolved scales particularly for the regions of low shear. Furthermore, the model appears to perform more accurately in the case of low density ratios. This study provides a proper perspective for future SGS models in the context of large eddy simulation of two-phase flows.

中文翻译：

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一种在两相 LES 的亚网格涡粘性中包含表面张力的新方法

摘要 与单相流相比，湍流两相流具有不同的湍动能产生和消散机制。然而，在为两相大涡模拟 (LES) 开发基于涡粘度的子网格尺度 (SGS) 模型时，通常会忽略这种差异。在这项研究中，提出了一种新的两相 LES 方法，将表面张力（小尺度运动中动能的产生机制）包括到亚网格涡粘性模型中。我们遵循基于流体体积 (VOF) 方法的界面流的 Favre 过滤控制方程，并推导出湍流动能的传输方程以包括表面张力的影响。本研究的最初贡献是基于混合长度假设提出了一种新的涡流粘度形式，其中包括源自界面功（即表面张力）的湍流动能的额外产生机制。建议的涡流粘度模型用于关闭所有 SGS 项。模型性能通过反相问题精细网格模拟的先验滤波来评估。为了测试模型在不同物理条件下的通用性，细网格模拟考虑了两种不同的密度比。结果突出了基于涡粘性的 SGS 模型在预测小未分辨尺度的湍动能方面的显着改进，特别是对于低剪切区域。此外，在低密度比的情况下，该模型似乎表现得更准确。本研究为未来 SGS 模型在两相流大涡模拟的背景下提供了适当的视角。