Turbulent two-phase flows abound in nature and engineering applications. The complex interactions between interfaces and turbulence strongly impact the flow properties. Consequently, there is both a scientific and industrial interest to study this two-way coupling phenomenon.
The objective is to use direct numerical simulation (DNS) to better understand this two-way coupling and to develop simulation tools adapted to industrial applications. In this perspective, we seek to develop a concept for two-phase flows that would be equivalent to the single-phase Large Eddy Simulation (LES).
In this concept, the interface geometry is fully resolved but part of the interactions between interface and turbulence is accounted for through dedicated subgrid models. The development of these models lies in particular on the analysis of a priori tests that allow to sort out the terms of the equations that require to be modeled. The most relevant of these DNS is the interaction of a strongly deformable bubble and a homogeneous isotropic turbulence (cf. image). The analysis of these results shows that it is necessary to use a modeling based on the Leonard and Germano decomposition, which provides subgrid models that integrate the two-way coupling phenomenon. An analysis based on the matched asymptotic expansion method allowed to determine the jump conditions that must be imposed at a under-resolved interface. The first results are very promising.