Heat and mass fluxes across a density interfaces submitted to a grid-generated turbulence

Abstract

The present study was first motivated by the industrial problem of the Liquefied Natural Gaz storage tank where the stratification between two different LNG layers could be destroyed by the increasing unstable thermal stratification. Then the choice was to reproduce the historical experiments of Turner with a thin stratified interface separating two homogeneous media mixed by oscillating grids. Comparisons between thermally or salinity stratified experiments exhibit the strong dependence of the flux on the molecular diffusivity. A phenomenological model is proposed for these transfer with a clear serial scheme which is different from the previous parallel ones. It gives a clear understanding of the influence of the molecular diffusivity on the flux across those density interfaces.