Multi-physics treatment in the vicinity of arbitrarily deformable gas–liquid interfaces

A novel three-dimensional problem formulation is introduced for the simulation of turbulent interfacial multi-fluid flows. The strategy is built around the large eddy simulation (LES) concept, and can be employed for interfacial heat and mass transfer problems in which use can be made of either scalar transfer correlations, or exact mass/energy jump conditions. This multi-physics treatment capability at arbitrarily deformable interfaces translates into two main features: (i) a reconstructed distance function (RDF) is introduced to define a level-set interface-normal length scale, and (ii) an interfacial shear velocity is defined on the distance function support for further use in near-interface transport models. The solution algorithm uses VOF with piecewise planar interface reconstructions on a twice-as-fine mesh, and infers the convective mass fluxes from the interface solution to promote momentum conservation. The interfacial shear velocity defined on the distance function support is introduced to accommodate the asymptotic behaviour of turbulence approaching the interface in a proximity-dependent manner. Provided with highly accurate distance function data, the scheme generates near-interface damping functions that are second-order accurate and independent of interface orientation. The damping was found to be affected by errors introduced into shear velocity estimates by the high-frequency errors in the RDF scheme near the interface. The methodology has been applied for the simulation of a wave breaking scenario featuring multiple modes and interfacial length scales.