This paper presents three volume of fluid (VoF)-based methods for large eddy simulations of atomizing sprays with different treatments of the unresolved interface. The turbulent filtered VoF model uses conventional turbulent viscosity models to close the combined interfacial and turbulent sub-grid fluctuations. The hybrid turbulence filtering and artificial compression model includes an additional artificial compression term that is applied along regions where the liquid–air interface is continuous, while conventional turbulence filtering is activated in regions with discrete liquid objects. The new explicit volume diffusion model (EVD) is based on the concept of averaging the VoF equations over explicitly defined physical volumes that are independent of the numerical grid. Closure models of the sub-volume flux and stress terms introduce explicit volume diffusion and explicit volume viscosity that are physically defined and linked to the volume size. Numerical convergence is achieved by reducing the grid size while keeping the explicit volume size constant. The models are tested for two experimental atomizing spray cases with different Weber numbers. The superior numerical convergence of the EVD model is demonstrated by analysis of the mean and rms of the volume fraction and velocity fields. Two models for the surface tension force are investigated for the EVD simulations. Compared with the simple surface tension model which neglects sub-grid fluctuations, an improved volume-averaged model based on fractal properties of wrinkled sub-volume interfaces gives better predictions of the mean volume fraction relative to the experimental data but requires selection of a model constant.

中文翻译：

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基于流体体积的数值收敛，基于雾化喷雾的大涡模拟

本文介绍了三种基于流体体积（VoF）的方法，用于对未解决界面进行不同处理的雾化喷雾的大涡模拟。湍流过滤后的VoF模型使用常规的湍流粘度模型来封闭界面和湍流子网格波动的组合。混合湍流过滤和人工压缩模型包括一个附加的人工压缩项，该术语沿液-气界面连续的区域应用，而常规湍流过滤在具有离散液体对象的区域中被激活。新的显式体积扩散模型（EVD）基于在与数字网格无关的显式定义物理体积上对VoF方程求平均值的概念。子体积通量和应力项的闭合模型引入了显式的体积扩散和显式的体积粘度，它们在物理上定义并与体积大小相关。通过减小网格大小，同时保持显式体积大小不变，可以实现数值收敛。对两个具有不同韦伯数的实验性雾化喷雾箱测试了该模型。通过分析体积分数和速度场的均值和均方根值，可以证明EVD模型具有出色的数值收敛性。对于EVD模拟，研究了两种表面张力的模型。与忽略亚电网波动的简单表面张力模型相比，