Efficient Implementation of Two-Phase Flow Solver Based on THINC/SW and S-CLSVOF on Unstructured Meshes

Abstract

This paper provides a practical implementation of a two-phase flow solver for Newtonian fluids with an immiscible interface. The solution procedure is composed of the tangent of hyperbola for interface capturing (THINC), the simple coupled level-set and volume of- fluid (S-CLSVOF) algorithm, and the density-scaled balanced continuum surface force (DSB-CSF) model. The newly introduced methods in the present study are 1) THINC with slope weighting (THINC/SW) extended to unstructured meshes and an 2) efficient initialization of the level-set function, which enables fewer iterations of the re-initialization. The validity and effectiveness of the present method are confirmed through three benchmark problems with comparison to other solvers. Regarding the accuracy of the interface advection, the present solver showed a sufficiently small error, which is comparable to the other established solvers. Regarding the re-initialization procedure of the level-set function, the number of iterations required by the proposed method is approximately half that required by a conventional method. For the benchmark problem on the thermocapillary flow in a rectangular cavity, it is confirmed that the present solver provides a solution sufficiently close to the asymptotic solution to this problem.