An ALE-FE method for two-phase flows with dynamic boundaries

The present work aims at developing a new flexible computational framework to simulate macro and microscale two-phase flows with dynamic boundaries. Such a technique is extremely useful for periodic and very large domains which requires exhaustive computational resources, consequently reducing the required numerical domain. In this article an interface tracking Finite Element (FE) method is used to solve the equations governing the motion of two immiscible incompressible fluids in the Arbitrary Lagrangian-Eulerian framework (ALE). The equations are written in axisymmetric coordinates, however the proposed moving boundary technique can be easily extended to 3-dimensional flows and other methods using the ALE framework such as the finite volume method. The two-phase interface separating the fluids is a subset of the domain mesh, therefore a layer of zero thickness is achieved assuring sharp transition of properties among phases. At the scale of interest, surface tension plays an important role and is thus considered in the flow equations. Several validations and results are presented for gravity dominated problem, including the sessile drop test and rising of spherical and Taylor bubbles, as well as the divergent and sinusoidal channels, showing accuracy for modeling two-phase flows in large and periodic domains. (C) 2020 Elsevier B.V. All rights reserved.