Hjs. Fernando et Jcr. Hunt, SOME ASPECTS OF TURBULENCE AND MIXING IN STABLY STRATIFIED LAYERS, Dynamics of atmospheres and oceans, 23(1-4), 1996, pp. 35-62
This paper presents a brief overview of recent work on turbulence and
mixing in stably stratified flows. It is concluded (1) that the usual
generalizations and 'scaling laws' of these flows need careful qualifi
cation, and (2) that the usual feature of unstratified turbulence of h
aving a single length scale for all large-scale processes may not be p
resent, especially when mean shear and buoyancy forcing have different
length scales and when there is significant wave motion (i,e. the Ozm
idov length scale is not the relevant macroscale), The second part of
the paper reviews the modeling of motions and mixing in stable density
interfaces interacting with contiguous layers of turbulence. Although
the rates of mass and momentum transfer across stratified interfaces
are much weaker than in unstratified turbulence, they play a crucial r
ole in the heat and mass balances in the atmosphere and oceans. The si
gnificant point is that these transfer rates are sensitive to the inte
rnal structure of the interface as well as to the overall Richardson n
umber determined by the buoyancy jump across the interface and externa
l turbulence.