Experimental analysis of lagrangian coherent structures and chaotic mixing in Rayleigh-Benard convection

Masahito Watanabe, Yusuke Kitamura, Naoki Hatta, Hiroaki Yoshimura

研究成果: Conference contribution

抄録

It is known that some fluid particles may be transported chaotically in Lagrangian description although the velocity field seems to be stable in Eulerian description. A typical example can be found in the system of two-dimensional Rayleigh-Benard convection with perturbed velocity fields, which has been investigated as a low dimensional mechanical model of fluid phenomena associated with natural convection in order to clarify the mechanism of fluid transport (see, for instance, [2]). In this study, we make an experimental study on the global structures of chaotic mixing appeared in the two-dimensional perturbed Rayleigh-Benard convection by analyzing Lagrangian coherent structures (LCSs), which correspond to the invariant manifolds of time-dependent mechanical systems. We develop an apparatus to measure the velocity field by Particle Image Velocimetry (PIV) and then show the LCSs which can be numerically detected from the experimental data by computing Finite-time Lyapunov exponent (FTLE) fields. Finally, we show the global structures of chaotic mixing appeared in the perturbed Rayleigh-Benard convection as well as the steady convection by experiments. In particular, we clarify how the LCSs are entangled with each other around the cell boundaries to carry out chaotic Lagrangian transports.

本文言語English
ホスト出版物のタイトルFluid Applications and Systems; Fluid Measurement and Instrumentation
出版社American Society of Mechanical Engineers (ASME)
ISBN(電子版)9780791883716
DOI
出版ステータスPublished - 2020
イベントASME 2020 Fluids Engineering Division Summer Meeting, FEDSM 2020, collocated with the ASME 2020 Heat Transfer Summer Conference and the ASME 2020 18th International Conference on Nanochannels, Microchannels, and Minichannels - Virtual, Online
継続期間: 2020 7 132020 7 15

出版物シリーズ

名前American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FEDSM
1
ISSN(印刷版)0888-8116

Conference

ConferenceASME 2020 Fluids Engineering Division Summer Meeting, FEDSM 2020, collocated with the ASME 2020 Heat Transfer Summer Conference and the ASME 2020 18th International Conference on Nanochannels, Microchannels, and Minichannels
CityVirtual, Online
Period20/7/1320/7/15

ASJC Scopus subject areas

  • 機械工学

フィンガープリント

「Experimental analysis of lagrangian coherent structures and chaotic mixing in Rayleigh-Benard convection」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

引用スタイル