An extended mixture model for the simultaneous treatment of small-scale and large-scale interfaces

The aim of this work is to present a new model based on the volume of fluid method and the algebraic slip mixture model in order to solve multiphase gas-fluid flows with different interface scales and the transition among them. The interface scale is characterized by a measure of the grid, which acts as a geometrical filter and is related with the accuracy in the solution; in this sense, the presented coupled model allows to reduce the grid requirements for a given accuracy. With this objective in mind, a generalization of the algebraic slip mixture model is proposed to solve problems involving small-scale and large-scale interfaces in an unified framework taking special care in preserving the conservativeness of the fluxes. This model is implemented using the OpenFOAM (R) libraries to generate a tool capable of solving large problems on high-performance computing facilities. Several examples are solved as a validation for the presented model, including new quantitative measurements to assess the advantages of the method. Copyright (c) 2014 John Wiley & Sons, Ltd.