Influence of boundary conditions in numerical simulation of free surface vortices

A numerical evaluation of gas core length in free surface vortices had been performed, applying different approaches. In the past only partial satisfactory agreement with experimental results was obtained because of an excessive simplification of the computational domain. In this work, two-phase CFD simulations (with Volume Of Fluid method) have been performed using a computational domain without any simplification and the evolution of the vortex formation has been analyzed in term of gas core length. Different turbulence models have been tested. A mesh sensitivity analysis has been performed. The new numerical results obtained with the most advanced turbulence model (SST SAS-CC) show an improved agreement with experimental data, with respect to the previous results, confirming the importance of imposing proper boundary conditions to correctly simulate free surface vortices.