A phase-field method for large-eddy simulation of two-phase slug flow in a pipe*

We present a phase-field method that enables large-eddy simulation (LES) of the initialization and development of the two-phase slugs formed in a stratified flow in a long horizontal pipe using realistic values of density ratio, viscosity ratio, Weber number and Reynolds number. The method is implemented in a spectral-element/Fourier code that makes the simulation  fast and very accurate.  The free interface is represented by the Cahn-Hilliard equation with interface compression that leads to excellent mass conservation. The Entropy Viscosity Method (EVM) is employed as LES subgrid eddy viscosity model.  The visualization of the simulation result exhibits the richness of the evolving topology of the slugs, while the predicted slug length and frequency are in good agreement with experimental measurements.