This work presents a numerical study of a skimming flow regime in a stepped spillway structure, which is a complex two-phase flow with self-aeration phenomenon. The numerical models employed consist in a hybrid approach capable of switching between interface resolving and interface modelling closures on a local level, and a state-of-the-art volume-of-fluid (VOF) method. A new switch criterion for the hybrid approach is proposed, allowing calculations on irregular grid cells. A detached eddy simulation (DES) turbulence model is selected in order to directly resolve the turbulent flow structures triggering the onset of self-aeration. The main flow properties computed in the non-aerated and aerated region are confronted with experimental measurements. Compared to the VOF method, the hybrid approach provides an overall better prediction of time-averaged air concentration, highlighting the positive outcome of modelling sub-grid interface structures.

这项工作对阶梯式溢洪道结构中的撇渣流态进行了数值研究，这是一种具有自曝气现象的复杂两相流。所采用的数值模型包括能够在局部水平的界面解析和界面建模闭合之间切换的混合方法，以及最先进的流体体积 (VOF) 方法。提出了混合方法的新切换标准，允许对不规则网格单元进行计算。选择分离涡流模拟 (DES) 湍流模型以直接解析触发自曝气开始的湍流结构。在非曝气和曝气区域计算的主要流动特性面临着实验测量。与VOF方法相比，