Large eddy simulation of turbulent interfacial flows using Approximate Deconvolution Model

摘要

Large eddy simulation (LES) is currently widespread in turbulence modeling research. Although LES has reached a mature level in modelling single-phase turbulent flows even in industrial scales, the challenges with LES of turbulent interfacial flows are still remaining. The main issue arises in subgrid closure modelling where the small-scale physics of the flow, as well as the small-scale interfacial topological changes, must be accounted for in filtered governing equations. In this paper, the Approximate Deconvolution Model (ADM) (Stolz and Adams, 1999) is extended to the two-phase LES problems to model all the subgrid terms appearing in the filtered governing equations. Then, the ADM-VOF approach is developed comprehensively and implemented in the frame of C++ libraries of OpenFOAM. The ADM-VOF is then employed for an a posteriori LES on the phase inversion benchmark which represents a buoyancy-driven turbulent interfacial flow with several interfacial events such as coalescence and rupture. To investigate the performance of this approach, a series of quantitative comparisons with quasi-DNS data and conventional LES (i.e. with single-phase assumption) is conducted based on macroscopic characteristics of the flow including enstrophy and interfacial length. The results reveal that the structural ADM-VOF approach improves the prediction of macroscopic flow characteristics associated with unresolved contributions compared to the conventional LES. The dependency of ADM-VOF performance on the grid resolution is also investigated. It shows that ADM-VOF exhibits more potentials in predicting the interfacial scales on a finer grid. Additionally, our study unveils that the choice of functional methods for modeling relaxation term may not be extendable to the two-phase ADM. (C) 2018 Elsevier Ltd. All rights reserved.