Assessment of performance of two-phase solvers for surface tension dominated flows related to lung airways

Comprehensive assessment of numerical accuracy of multiphase flow solvers is essential for establishing reliable guidelines in applications where capillary forces dominate such as in pulmonary bioflows. This study evaluates the relative performance of three interface-capturing methods widely used in two-phase flow simulations: algebraic Volume of Fluid ( OpenFOAM VOF ) and coupled Level-Set/VOF ( OpenFOAM S-CLSVOF ) implemented in OpenFOAM, and geometric VOF implemented in Basilisk ( Basilisk VOF ). The benchmark cases selected include classical rising bubble and droplet impact problems, designed to test numerical accuracy and efficiency of the solvers in surface tension dominated flows. Further performance assessment is done considering physiologically relevant microfluidic configurations including Taylor flow and liquid plug propagation. Results show that OpenFOAM S-CLSVOF and Basilisk VOF outperform OpenFOAM VOF in capturing interface dynamics and resolving capillary-dominated flows, particularly at finer spatial and temporal resolutions. The study aims to guide solver selection and parameter tuning for biomedical multiphase simulations, especially in applications involving plug propagation and plug rupture in lower airways.