In this article, we present a full three-dimensional numerical study of thin liquid films falling on a vertical surface, by solving the full three-dimensional Navier–Stokes equations with a hybrid front-tracking/level-set method for tracking the interface. General falling film flow applications span across many types of process industries but also occur in a multitude of natural and environmental applications such as ice sheets, glaciology and even volcanic lava flows. In this study, we propose three configurations of falling films. Two of them, with small and moderate Reynolds number, are set to mimic pulsed and forced falling film types inside a minimum periodic domain, able to cover entirely the temporal evolution of a single wave. The latest example, corresponding to a high Reynolds number, is initialised with a flat interface without any specific perturbations. For the first time, this study highlights the natural transition from a non-deformed interface to its first streamwise disturbance (two-dimensional wavy flow), and then a second spanwise wave disturbance (three-dimensional wavy flow).

在本文中，我们通过使用用于跟踪界面的混合前跟踪/水平集方法求解完整的三维 Navier-Stokes 方程，对落在垂直表面上的薄液膜进行了完整的三维数值研究。一般降膜流应用跨越多种类型的加工工业，但也出现在多种自然和环境应用中，例如冰盖、冰川甚至火山熔岩流。在这项研究中，我们提出了三种降膜配置。其中两个具有小而适中的雷诺数，被设置为模拟最小周期域内的脉冲和强制降膜类型，能够完全覆盖单个波的时间演化。最新的例子，对应于高雷诺数，使用平面接口初始化，没有任何特定的扰动。本研究首次强调了从非变形界面到其第一次流向扰动（二维波浪流），然后是第二次展向波浪扰动（三维波浪流）的自然过渡。