The accuracy of large eddy simulation (LES) is highly dependent on the performance of sub-grid scale (SGS) model. In the present paper, a dynamic cubic nonlinear sub-grid scale model (DCNM) proposed by Huang et al. is implemented for the simulation of unsteady cavitating flow around a 3-D Clark-Y hydrofoil in OpenFOAM. Its performance in predicting the evolution of cloud cavitation is discussed in detail. The simulation with a linear model, the dynamic Smagorinsky model (DSM), is also conducted as a comparison. The results with DCNM show a better agreement with the available experimental observation. The comparison between DCNM and DSM further suggests that the DCNM is able to predict the backscatter more precisely, which is an important feature in LES. The characteristics of DCNM is analyzed to account for its advantages in the prediction of unsteady cloud cavitation as well. The results reveal that it is the nonlinear terms of DCNM that makes DCNM capture sub-grid scale vortices better and more suitable for studying the transient behaviors of cloud cavitation than DSM.

中文翻译：

---

在OpenFOAM中使用动态立方非线性子网格比例模型对湍流空化流进行数值模拟的一些注意事项

大涡模拟（LES）的准确性高度依赖于子网格规模（SGS）模型的性能。在本文中，由Huang等人提出的动态三次非线性子网格比例模型（DCNM）。用于模拟OpenFOAM中3-D Clark-Y水翼周围的非稳态空化流。详细讨论了其在预测云空化演变方面的性能。作为比较，还使用线性模型（动态Smagorinsky模型（DSM））进行了仿真。DCNM的结果与可用的实验观察结果更好地吻合。DCNM和DSM之间的比较进一步表明DCNM能够更精确地预测反向散射，这是LES中的重要功能。分析了DCNM的特性以说明其在预测非稳定云空化方面的优势。结果表明，正是DCNM的非线性项使得DCNM捕获亚网格尺度的涡旋比DSM更好，更适合于研究云空化的瞬态行为。