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SUMMARY:A shallow-water theory of annular sections of cold astrophysical d
 isks - Orkan Umurhan (Queen Mary)
DTSTART:20081124T160000Z
DTEND:20081124T170000Z
UID:TALK13126@talks.cam.ac.uk
CONTACT:Dr Geoffroy Lesur
DESCRIPTION:Astrophysical disks are characterized by order unity Rossby nu
 mbers.  This makes the analysis of their vortical disturbances difficult t
 o perform in terms of classical geostrophic flow approximations.  In this 
 study a scaling analysis is motivated and an asymptotic reduction of the e
 quations of motion are presented which addresses this issue.  The resultin
 g equations describe motion which is geostrophic in the radial and hydrost
 atic in the vertical.  An analysis of a series of simple problems is prese
 nted.  In one problem an incarnation of the stratorotational instability i
 s recovered.  In another\, the nonlinear evolution of an unstable Rossby w
 ave is studied using weakly nonlinear techniques (single-wave theory).  A 
 discussion is presented discussing both the limitations of the theory and 
 future directions.
LOCATION:MR14\, DAMTP\, Pav. F
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