Numerical Simulation of Free Surface Flows Using STACS-VOF Method

This paper presents a numerical method that couples the incompressible Navier-Stokes equations with the Volume of Fluid method in a Cartesian co-ordinate system for tracking immiscible interfaces in multiple dimensions. The governing equations are discretized based on a finite volume method on a non-staggered fixed grid. The free surface flow problem is solved as a single phase flow system in which the free surface is captured using a Switching Technique for Advection and Capturing of Surfaces (STACS) scheme. The effects of surface tension at the interfaces are treated using a Continuum Surface Force (CSF) model. The pressure velocity coupling is achieved using a SIMPLE strategy. The coupled system, implemented in the commercial CFD software, AVL FIRE/SWIFT, is applied to a two dimensional dam breaking problem. The simulation results reveal a multitude of phenomena such as, free surface vortex generation, air entrapment and splashing of the liquid surge front. The computational results are in good agreement with experimental data, wherever available. The effects of time and grid resolution on the solution behavior are elaborated in detail. Different convection schemes are tested and the current method is compared to another existing interface capturing methodology.