流体力学セミナー流体力学セミナー

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流体力学セミナー ２０１０

＃ 3 / 10 水曜日の開催となっています．ご注意ください．

＃数理解析研究所の建物耐震改修工事のため，場所が京大理学部物理教室
　になっています．ご注意ください．

日時： 3月10日（水） 15:00 から 16:30

場所： 京大 理学研究科5号館（物理学教室）525号室 (第4講義室)

講師： Paul Manneville (Ecole Polytechnique)

題目: Decay of turbulence in plane Couette flow:
turbulent bands from the lab to the computer

概要：The bifurcation diagram of plane Couette flow is characteristic
of flows without linear instability modes. After a brief
presentation of experimental findings obtained in Saclay at the
turn of the century, supporting a distinction between an upper
transitional range with oblique bands and a lower transitional
range with decaying spots, a brief review of the numerical
approaches taken up to now will be given, with special emphasis
on the ‘temporal / spatiotemporal’ issue. In order to reach
large aspect ratios, a modelling strategy having recourse to a
drastic lowering of the cross-stream resolution has been developed.
A first semianalytical approach [1] points to an interpretation
in terms of spatiotemporal intermittency [2] proposed by Pomeau
but fails to reproduce the bands, which is not the case of the
under-resolved direct numerical simulations that we have performed
using Gibson’s ChannelFlow program. These simulations faithfully
reproduce experimental findings up to a measurable shift of the
transitional range [3], which shows that the formation of bands
is a robust phenomenon involving gross features of the turbulent
flow only.

[1] M. Lagha, P. M., “Modeling transitional plane Couette flow,”
Eur. Phys. J. B, vol. 58 (2007) 433–447.
[2] P. M., “Spatiotemporal perspective on the decay of turbulence in
wall-bounded flows” Phys. Rev. E; vol. 79 (2009) 025301 [R]; 039904 [E].
[3] J. Rolland, P.M., “Numerical approach to the simulation of plane
Couette flow in extended geometry” in preparation for Theor. Comp. Fluid Dyn.

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世話人：山田 道夫(京大数理研)， 藤 定義(京大)，松本 剛(京大理)
アドバイザー：船越 満明（京大情報学）、水島 二郎(同志社大工)、
余田 成男（京大理）
連絡先：山田道夫 yamada@kurims.kyoto-u.ac.jp
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