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Hysteresis and Wavenumber Vacillation in Unstable Baroclinic FlowsHysteresis and wavenumber vacillation are studied numerically in a weakly stratified quasigeostrophic model. In general, the amplitude of the most unstable wave increases, as the flow becomes more unstable. When the wave becomes saturated, the next longer wave will grow at the expanse of the most unstable wave and becomes the dominant wave. However, once the longwave state is established, it may remain in that regime even as the instability is decreased beyond the threshold where it first developed, thus constituting a hysteresis loop. In a highly unstable case, the flow may not show a preference for any single wave. Instead, the dominant wave aperiodically varies among several long waves. This phenomenon is known as wavenumber vacillation. Hysteresis is further examined in terms of eddy heat flux. It is shown that total eddy heat flux increases as the flow becomes more unstable, but displays a sharp drop when transition to a longer wave occurs. However, in a longwave state, the heat flux always decreases with decreasing instability even pass the threshold when wave transition first occurs.
Document ID
20010038450
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Chou, Shih-Hung
(NASA Marshall Space Flight Center Huntsville, AL United States)
Goodman, H. Michael
Date Acquired
August 20, 2013
Publication Date
January 1, 2001
Subject Category
Fluid Mechanics And Thermodynamics
Meeting Information
Meeting: Wave Phenomena III: Waves in Fluids from the Microscopic to the Planetary Scale
Location: Edmonton
Country: Canada
Start Date: June 11, 2001
End Date: June 15, 2001
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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