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The Effect of Shear Instability on the Transverse Circulation in the Atmosphere


Stewart, Homer Joseph (1940) The Effect of Shear Instability on the Transverse Circulation in the Atmosphere. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/1FW3-YN51.


In this paper it is shown that the shear fields on either side of the westerlies are dynamically unstable and will roll up to form discrete eddies. A study of the stable vortex systems into which these eddies might collect shows that a "vortex street" is stable for a certain range of the ratio of width to vortex spacing. It is also shown that a formation with vortices placed on the corners of a regular polygon is stable if the number of vortices is less than seven. This still holds if the effect of the shear field north of the westerlies is stimulated by a fixed polar cyclone. It further appears that with a strong general circulation, i.e. strong westerlies, only two or three high pressure cells should be found while the numbers, up to six, should be found with weaker circulations. This conclusion is verified by Northern Hemisphere mean pressure charts.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Aeronautics)
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Aeronautics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • von Kármán, Theodore
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1940
Record Number:CaltechETD:etd-05222003-084939
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1931
Deposited By: Imported from ETD-db
Deposited On:22 May 2003
Last Modified:17 Aug 2023 00:19

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PDF (Stewart_hj_1940.pdf) - Final Version
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