Time-dependent fluxes across double-diffusive interfaces

Abstract

A simple, time-dependent model is proposed to predict the heat and salt fluxes transferred between a hot, salty fluid layer and an overlying colder, fresher fluid layer when the overall density of the lower layer is greater than that of the upper layer. The interface separating the two layers, known as a ‘diffusive’ interface, consists of a purely diffusing core sandwiched between vigorously convecting boundary layers. This type of interface occurs whenever the density of superposed fluid layers depends on two diffusing agents with different diffusivities such that the faster diffusing agent causes a statically unstable density variation while the slower diffusing agent causes a statically stable variation. Early experimental and theoretical studies sought a single relationship between the heat flux , and both links and puts into context two previous theories of diffusive interfaces.