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Three‐dimensional evolution of Kelvin‐Helmholtz billows in stratified compressible flow
Author(s) -
Palmer Teresa L.,
Fritts David C.,
Andreassen Øyvind,
Lie Ivar
Publication year - 1994
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/94gl01714
Subject(s) - vortex , buoyancy , instability , mechanics , stratified flow , shear flow , physics , stratified flows , reynolds number , baroclinity , compressibility , turbulence , classical mechanics , richardson number , mean flow , geology
We present results of an initial study of Kelvin‐Helmholtz instability in a stratified shear flow using a three‐dimensional, nonlinear, compressible, spectral collocation model. The simulation was performed at an intermediate Reynolds number and significantly extends previous studies of homogeneous and stratified shear flows. Our major findings include a secondary instability oriented along the two dimensional velocity field, with counter‐rotating vortices arising due to both buoyancy and shear sources of eddy kinetic energy within the billow structures. The vortices occupy the outer regions of the billows and contribute significant eddy transports of momentum and potential temperature within the billows. The resulting KH evolution differs in important respects from the corresponding two‐dimensional or unstratified flows.