A coastal eddy is modelled as a barotropic vortex propagating along a coastal shelf. If the vortex speed matches the phase speed of any coastal trapped shelf wave modes, a shelf wave wake is generated leading to a flux of energy from the vortex into the wave field. Using a simple shelf geometry, we determine analytic expressions for the wave wake and the leading-order flux of wave energy. By considering the balance of energy between the vortex and wave field, this energy flux is then used to make analytic predictions for the evolution of the vortex speed and radius under the assumption that the vortex structure remains self-similar. These predictions are examined in the asymptotic limit of small rotation rate and shelf slope and tested against numerical simulations. If the vortex speed does not match the phase speed of any shelf wave, steady vortex solutions are expected to exist. We present a numerical approach for finding these nonlinear solutions and examine the parameter dependence of their structure.
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The Propagation and Decay of a Coastal Vortex on a Shelf
A coastal eddy is modelled as a barotropic vortex propagating along a coastal shelf. If
the vortex speed matches the phase speed of any coastal trapped shelf wave modes, a
shelf wave wake is generated leading to a
ux of energy from the vortex into the wave
eld. Using a simply shelf geometry, we determine analytic expressions for the wave wake
and the leading order
ux of wave energy. By considering the balance of energy between
the vortex and wave eld, this energy
ux is then used to make analytic predictions
for the evolution of the vortex speed and radius under the assumption that the vortex
structure remains self similar. These predictions are examined in the asymptotic limit of
small rotation rate and shelf slope and tested against numerical simulations.
If the vortex speed does not match the phase speed of any shelf wave, steady vortex
solutions are expected to exist. We present a numerical approach for nding these
nonlinear solutions and examine the parameter dependence of their structure.
more »
« less
- Award ID(s):
- 1941963
- NSF-PAR ID:
- 10269827
- Date Published:
- Journal Name:
- Journal of fluid mechanics
- ISSN:
- 1469-7645
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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