Dynamics of localized vorticity perturbations in shear flow

                         by
 
              Diego del-Castillo-Negrete
             (Scripps Oceanographic Inst.)  

             JTB 120, 3:20pm  Monday, March 9, 1998


                          Abstract
 
Matched asymptotic expansions are used to reduced the two dimensional
Navier-Stokes equation to a simpler equation describing the nonlinear
evolution of localized vorticity perturbations in shear flow.
The linear theory of the reduced equation is discussed in a concise
and complete form, and numerical results are presented in the nonlinear
regime. Using weakly nonlinear theory, a further  reduction is done to
study the case of marginally stable flows. We present exact and
numerical  solutions  of the weakly  nonlinear  equations illustrating
the formation of coherent  structures, the growth and saturation of
instabilities,  transient  growth  of stable  perturbations,  chaotic
vorticity mixing, and marginally stability relaxation. If time  permits,
we will discuss how the previous  ideas can be applied to plasma physics.


Requests for preprints and reprints to: diego@saffy.ucsd.edu
This source can be found at http://www.math.utah.edu/applied-math/