社会創造数学研究セミナー

講演タイトル：Dynamical Barriers to Front Propagation in Active Fluid
Flows

場所：電子科学研究所（北キャンパス）１階セミナー室1-3
http://www.es.hokudai.ac.jp/about/index.html

日時：8月17日17:00-18:00

講師：Kevin Mitchell
Professor and Founding Faculty
School of Natural Sciences
University of California, Merced
http://www.ucmerced.edu/content/kevin-mitchell

講演要旨：
The passive advection of inert particles in fluid flows is important
both for its direct relevance to fluid mixing and for its broader
connection to Hamiltonian dynamics and chaos.  This talk considers the
generalization of advective transport to “active” media, specifically
to media that support some kind of front propagation: for example, the
expansion of chemical reaction fronts in microfluidic mixers, plankton
blooms in large-scale oceanic flows, phase transitions in liquid
crystals, or even the spread of disease within a mixing population.  A
low-dimensional nonlinear dynamics model is used to predict the
existence–and to explain the properties–of robust, one-sided
barriers to front propagation.  We call these barriers Burning
Invariant Manifolds (BIMs).  BIMs play a central role in guiding the
propagating fronts through the medium, determining the patterns formed
by the fronts, and in determining the average propagation speeds.  We
compare our theory to table-top experiments in
magneto-hydrodynamically driven flows, and we highlight the role of
BIMs for experimental phenomena, such as the mode-locking and pinning
of reaction fronts.  Finally, we introduce a theory of burning
Lagrangian Coherent Structures (bLCSs), which are generalizations of
BIMs to the more challenging problem of front propagation in unsteady,
aperiodic fluid flow.

セミナーの後で、Mitchell先生を囲んで夕食を予定しております。ご参加をご希
望される場合にはご連絡いただければ幸いです。

連絡先

小松崎 民樹
北海道大学電子科学研究所
附属社会創造数学研究センター（データ数理研究分野）
〒001-0020 札幌市北区北20条西10丁目
TEL&FAX:011-706-9434
E-mail: tamiki( at )es.hokudai.ac.jp
URL: http://mlns.es.hokudai.ac.jp