| 日時： |
2007年01月29日（月） 14:00〜15:00 |
| 場所： |
京都大学大学院 工学研究科 航空宇宙工学専攻（工学部11号館） 2階 第2講義室 |
| 講演者： |
Prof. Tom Mullin (Manchester Centre for Nonlinear Dynamics, Department of Physics and Astronomy, The University of Manchester) |
| 講演題目： |
Recent observations on transition to turbulence in pipe flow |
| 講演要旨： |
The puzzle of why fluid motion along a pipe is observed to become turbulent as the flow rate is increased remains the outstanding challenge of hydrodynamic stability theory, despite more than a century of research. The issue is both of deep scientific and engineering interest since most pipe flows are turbulent in practice even at modest flow rates. All theoretical work indicates that the flow is linearly stable i.e. infinitesimal disturbances decay as they propagate along the pipe and the flow will remain laminar. Finite amplitude perturbations are responsible for triggering turbulence and these become more important as the non-dimensionalized flow rate, the Reynolds number R, increases. We will address the question of what happens to perturbations close to the threshold for transition and discuss connections with critical behaviour in other systems. |
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