21世紀COE特別講演
Date : |
12月 5日 (月) 15:00〜16:30
|
Place : |
数理研009号室
|
Lecturer: |
Alex D.D. Craik
(University of St Andrews)
|
Title : |
On the development of singularities in linear dispersive systems
|
Abstract: |
Benilov, O'Brien & Sazonov (2003) and Benilov (2004) describe "a new
type of instability" in a liquid film inside a rotating cylinder.
Though their linear systems support only neutrally-stable modes, they
find explosive disturbances which become singular after a finite
time. They suggest that this result casts doubt on the reliability of
modal analysis for prediction of instability; and they claim that
"Such cases have never been described in the literature, and they are
probably extremely rare." Here, other examples are given, some of
which have been known (though not well-known) for many years. A
common feature of all these singularities is a local phase
synchronisation of short-wave modes; but the configuration of Benilov
et al. has the additional feature of eigenfunctions that exhibit very
large changes in amplitude within the spatial domain. The relevance,
or not, of such singularities to real physical systems is discussed
|
担当:岡本 久
|
|