Many different phenomena in industry or nature include a deformable interface for example the water falling from a spillway. The simulation of such events is essential to better understanding of two-phase flow behavior, in order to optimize the design or to calculate hydrodynamic coefficients. The precise and correct modeling of interface is the key parameter in simulation of free surface. There are different interface tracking methods such as VoF (volume of fluid), LS (level set) and FT (front tracking). Each method has its own advantages and disadvantages, however VoF is becoming the most common interface tracking method due to it’s ease of implementation and mass conservation. OpenFOAM VoF solver is interFoam. The solver uses a technique called MULES to compress the interface and return the sharp interface. The interFoam is suitable for two-phase isothermal incompressible system. The derived solvers form interFoam is: