In this paper, we present a new model to simulate the formation, evolution, and break-up of a thin film of fluid flowing over a curved surface. Referred to as the discrete droplet method (DDM), the model captures the evolution of thin fluid films by tracking individual moving fluid droplets. In contrast to existing thin-film models that solve a PDE to determine the film height, here, we compute the film height by numerical integration based on the aggregation of droplets. The novelty of this approach in using droplets makes it suitable for simulating the formation of fluid films, and modelling thin film flows on partially wetted surfaces. The DDM is a Lagrangian approach, with a force balance on each droplet governing the motion, and derivatives approximated using a smoothed particle hydrodynamics (SPH) like approach. The proposed model is thoroughly validated by comparing results against analytical solutions, against the results of the shallow-water equations for thin film flow, and also against results from a full 3-D resolved Navier–Stokes model. We also present the use of the DDM on an industrial test case. The results highlight the effectiveness of the model for simulations of flows with thin films.

在本文中，我们提出了一个新模型来模拟在曲面上流动的流体薄膜的形成、演化和破裂。该模型称为离散液滴法 (DDM)，通过跟踪单个移动的液滴来捕捉薄液膜的演变。与解决 PDE 的现有薄膜模型相比为了确定膜高，在这里，我们通过基于液滴聚集的数值积分来计算膜高。这种使用液滴的方法的新颖性使其适用于模拟流体膜的形成，以及模拟部分润湿表面上的薄膜流动。DDM 是一种拉格朗日方法，每个液滴上的力平衡控制运动，并且使用类似平滑粒子流体动力学 (SPH) 的方法来近似导数。通过将结果与解析解、薄膜流动的浅水方程结果以及完整的 3-D 解析 Navier-Stokes 模型的结果进行比较，对所提出的模型进行了彻底验证。我们还介绍了 DDM 在工业测试用例中的使用。