Nonlinear dissipative critical level interaction in a stratified shear flow: Instabilities and gravity waves
作者:
Françlois Lott,
Hector Teitelbaum,
期刊:
Geophysical & Astrophysical Fluid Dynamics
(Taylor Available online 1992)
卷期:
Volume 66,
issue 1-4
页码: 133-167
ISSN:0309-1929
年代: 1992
DOI:10.1080/03091929208229054
出版商: Taylor & Francis Group
关键词: Gravity waves;Kelvin-Helmholtz instabilities;nonlinear critical layer;dissipation;Prandtl number
数据来源: Taylor
摘要:
A two-dimensional numerical model is used to investigate the nonlinear dissipative interaction between a disturbance and an unbounded stratified shear flow. The disturbances considered are Kelvin-Helmholtz instabilities and forced gravity waves. The nonlinear stabilization (destabilization) of Kelvin-Helmholtz instabilities at Prandtl number,Pr< 1 (Pr> 1), found by Brownet al.(1981) is recovered. The model confirms that it is mostly due to a stabilization (destabilization) of the mean flow by the wave. The nonlinear evolution of instabilities existing when thermal dissipation is large and when the Richardson number is everywhere larger than 0.25 is also investigated. It is shown that such a mode stops growing when the nonlinear distortion of the mean flow becomes significant.
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