Investigation on turbulence-interface interactions in liquid-liquid flows using ADM-VOF method and time-resolved PIV

n this work the interactions of turbulence with the liquid-liquid interfaces of an incompressible two-phase flow are investigated numerically and experimentally. A new large eddy simulation formulation is employed where all the subgrid scale (SGS) terms are modelled using an approximate deconvolution-based volume of fluid approach (ADM-VOF). In this structural turbulence modelling method, the SGS terms of stress tensor and surface tension in the Navier-Stokes equations as well as the interface dynamics in the VOF advection equation are mathematically reconstructed from the resolved scales. An in-house benchmark experiment was designed to measure the turbulent flow fields in the vicinity of the interfaces using time-resolved particle image velocimetry (TR-PIV) technique. For better comparison, additional simulations were performed using a conventional LES in which only convective SGS term is modelled using an eddy-viscosity approach. The statistics of interfacial turbulence including velocity fluctuations and interface dynamics are then analyzed numerically and validated against the experimental data. It is observed that the interface suppresses the turbulent energy level. The results also highlight the effect of subgrid scale turbulence-interface interactions which leads to superior performance of the ADM-VOF approach in predicting the turbulent energy spectra and statistics of interface dynamics compared to conventional LES.