Modeling of subgrid-scale interfacial area for turbulent two-phase flows

Interfacial exchange of mass, momentum, and energy is directly proportional to the amount of interfacial surface area. Hence, an accurate prediction of the interfacial surface area is vital for modeling these transfer processes. However, numerically resolving all the interfacial area corrugations down to the Hinze scale in a turbulent flow is prohibitively expensive due to the large separation of scales. This necessitates an alternate modeling strategy.

Interfacial area has been previously modeled in the framework of Reynolds-averaged Navier Stokes equations (RANS) equations (Kocamustafaogullari and Ishii, IJHMT, 1995) using phenomenological approaches. However, in the context of a large-eddy simulation (LES) of two-phase flows, where an interface-capturing/tracking method is used for resolving interfaces, coarse LES grids will underpredict the interfacial area. The present work uses direct numerical simulations and LES calculations to quantify and model this missing subgrid interfacial area in the context of LES of turbulent two-phase flows. This study has applications in engineering and natural processes, such as atomization and oceanic gas transfer.