Math Annex 1100
University of Toronto
Nonlinear critical layer interactions of wave packets in the atmosphere
A mathematical difficulty that arises in the linear, inviscid
theory of waves in shear flows is that a singularity is generally
present if there is a point where the mean flow velocity is equal
to the phase speed of the perturbation. In the critical layer
centred upon such a point, incident waves may be absorbed by the
mean flow and, when nonlinear effects are included in the
governing equations, wave breaking and reflection sometimes occur.
There are several atmospheric phenomena which are known to result
from wave-mean-flow interactions, for example, the quasi-biennial oscillation (QBO) which is observed in the tropical stratosphere.
In this talk, I shall describe numerical and asymptotic studies
of the nonlinear evolution of forced wave packets at critical layers.
Refreshments will be served at 2:45 p.m. in the Faculty Lounge,
Math Annex (Room 1115).