Simulation of the two-fluid model on incompressible flow with Fractional Step method for both resolved and unresolved scale interfaces

• Two phase flow with free surface is solved by means of two-fluid model (TFM).
• Fractional Step method and finite volume technique is used to solve TFM.
• Conservative Level Set method reduces interface sharpening diffusion problem.
• Cases including high density ratios and high viscosities validate the models.

In the present paper, the Fractional Step method usually used in single fluid flow is here extended and applied for the two-fluid model resolution using the finite volume discretization. The use of a projection method resolution instead of the usual pressure-correction method for multi-fluid flow, successfully avoids iteration processes. On the other hand, the main weakness of the two fluid model used for simulations of free surface flows, which is the numerical diffusion of the interface, is also solved by means of the conservative Level Set method (interface sharpening) (Strubelj et al., 2009). Moreover, the use of the algorithm proposed has allowed presenting different free-surface cases with or without Level Set implementation even under coarse meshes under a wide range of density ratios. Thus, the numerical results presented, numerically verified, experimentally validated and converged under high density ratios, shows the capability and reliability of this resolution method for both mixed and unmixed flows.