In this study, a laboratory experiment was conducted to investigate quantitatively turbulent exchange between two quasi-homogeneous layers of equal thickness and different density (salinity), as well the fine structure transition zone (interface) layers. The fluid continuously stirred by system horizontally oscillating vertical rods, piercing through both producing vertically homogeneous impact...

Diffusion-driven flow arises when a stably stratified fluid is bounded by an inclined wall. For a stratified fluid in an inclined fissure, in which fluid is confined to a gap between two inclined parallel walls, the flow field is determined by the gap width and the angle of inclination. When the gap width is much wider than the buoyancy layer thickness, the problem reduces to that of a semi-inf...

It is shown by way of nonlinear numerical simulations of flow restricted to two dimensions that a compact wavepacket of large-amplitude internal gravity waves incident upon a weakly stratified region in which the buoyancy frequency is less than the frequency of the wavepacket may partially transmit energy into this region through the generation of a wavepacket of lower frequency. In part, the t...

Water stratified thermally or with dissolved material has a refractive index that varies with height. The stratification has no obvious visual effect until the fluid is disturbed, for example by a fish, but then it marks the creature's wake with a jump in refractive index that is visible in shadowgraphic projection. Two shadowgraphs in stereo display the wake in three dimensions. For a permanen...

Rotating grid turbulence experiments have been carried out in a stably stratified fluid for relatively large Reynolds numbers (mesh Reynolds numbers up to 18 000). Under the combined effects of rotation and stratification the flow degenerates into quasihorizontal motions. This regime is investigated using a scanning imaging velocimetry technique which provides time-resolved velocity fields in a...

We study the inviscid damping of Couette flow with an exponentially stratified density. The optimal decay rates of the velocity field and the density are obtained for general perturbations with minimal regularity. For Boussinesq approximation model, the decay rates we get are consistent with the previous results in the literature. We also study the decay rates for the full Euler equations of st...

Problem StatusAuthorizationIntroductionNumerical AnalysisResults and DiscussionReferencesil11ii12813

A simple exact solution of the Boussinesq equations of motion, thermal energy, and mass conservation is obtained for an oscillatory flow regime in a stably stratified rotating fluid. The flow is unbounded and characterized by velocity gradients that vary with time but are spatially uniform—the basic state of Craik-Criminale flows. The solution describes an oscillatory convergent-divergent flow ...

The flow of a continuously stratified fluid into a contraction is examined, under the assumptions that the dynamic pressure and the density gradient are constant upstream (Long’s model). It is shown that a solution to the equations exists if and only if the strength of the contraction does not exceed a certain critical value which depends on the internal Froude number. For the flow of a stratif...

This paper formulates a model of mixing in a stratified and turbulent fluid. The model uses the horizontally averaged vertical buoyancy gradient and the density of turbulent kinetic energy as variables. Heuristic ‘mixing-length’ arguments lead to a coupled set of parabolic differential equations. A particular form of mechanical forcing is proposed; for certain parameter values the relationship ...