Time-dependent diffusion coefficients for chaotic advection due to fluctuations of convective rolls

Kazuma Yamanaka, Takayuki Narumi, Megumi Hashiguchi, Hirotaka Okabe, Kazuhiro Hara, Yoshiki Hidaka

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The properties of chaotic advection arising from defect turbulence, that is, weak turbulence in the electroconvection of nematic liquid crystals, were experimentally investigated. Defect turbulence is a phenomenon in which fluctuations of convective rolls arise and are globally disturbed while maintaining convective rolls locally. The time-dependent diffusion coefficient, as measured from the motion of a tagged particle driven by the turbulence, was used to clarify the dependence of the type of diffusion on coarse-graining time. The results showed that, as coarse-graining time increases, the type of diffusion changes from superdiffusion ? subdiffusion ? normal diffusion. The change in diffusive properties over the observed timescale reflects the coexistence of local order and global disorder in the defect turbulence.

Original languageEnglish
Article number99
JournalFluids
Volume3
Issue number4
DOIs
Publication statusPublished - Dec 1 2018

Fingerprint

Advection
advection
Turbulence
diffusion coefficient
turbulence
Defects
defects
Nematic liquid crystals
liquid crystals
disorders

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering
  • Fluid Flow and Transfer Processes
  • Condensed Matter Physics

Cite this

Time-dependent diffusion coefficients for chaotic advection due to fluctuations of convective rolls. / Yamanaka, Kazuma; Narumi, Takayuki; Hashiguchi, Megumi; Okabe, Hirotaka; Hara, Kazuhiro; Hidaka, Yoshiki.

In: Fluids, Vol. 3, No. 4, 99, 01.12.2018.

Research output: Contribution to journalArticle

@article{139204b74cf34e3c9a3473a08a4b167e,
title = "Time-dependent diffusion coefficients for chaotic advection due to fluctuations of convective rolls",
abstract = "The properties of chaotic advection arising from defect turbulence, that is, weak turbulence in the electroconvection of nematic liquid crystals, were experimentally investigated. Defect turbulence is a phenomenon in which fluctuations of convective rolls arise and are globally disturbed while maintaining convective rolls locally. The time-dependent diffusion coefficient, as measured from the motion of a tagged particle driven by the turbulence, was used to clarify the dependence of the type of diffusion on coarse-graining time. The results showed that, as coarse-graining time increases, the type of diffusion changes from superdiffusion ? subdiffusion ? normal diffusion. The change in diffusive properties over the observed timescale reflects the coexistence of local order and global disorder in the defect turbulence.",
author = "Kazuma Yamanaka and Takayuki Narumi and Megumi Hashiguchi and Hirotaka Okabe and Kazuhiro Hara and Yoshiki Hidaka",
year = "2018",
month = "12",
day = "1",
doi = "10.3390/fluids3040099",
language = "English",
volume = "3",
journal = "Fluids",
issn = "2311-5521",
publisher = "Multidisciplinary Digital Publishing Institute",
number = "4",

}

TY - JOUR

T1 - Time-dependent diffusion coefficients for chaotic advection due to fluctuations of convective rolls

AU - Yamanaka, Kazuma

AU - Narumi, Takayuki

AU - Hashiguchi, Megumi

AU - Okabe, Hirotaka

AU - Hara, Kazuhiro

AU - Hidaka, Yoshiki

PY - 2018/12/1

Y1 - 2018/12/1

N2 - The properties of chaotic advection arising from defect turbulence, that is, weak turbulence in the electroconvection of nematic liquid crystals, were experimentally investigated. Defect turbulence is a phenomenon in which fluctuations of convective rolls arise and are globally disturbed while maintaining convective rolls locally. The time-dependent diffusion coefficient, as measured from the motion of a tagged particle driven by the turbulence, was used to clarify the dependence of the type of diffusion on coarse-graining time. The results showed that, as coarse-graining time increases, the type of diffusion changes from superdiffusion ? subdiffusion ? normal diffusion. The change in diffusive properties over the observed timescale reflects the coexistence of local order and global disorder in the defect turbulence.

AB - The properties of chaotic advection arising from defect turbulence, that is, weak turbulence in the electroconvection of nematic liquid crystals, were experimentally investigated. Defect turbulence is a phenomenon in which fluctuations of convective rolls arise and are globally disturbed while maintaining convective rolls locally. The time-dependent diffusion coefficient, as measured from the motion of a tagged particle driven by the turbulence, was used to clarify the dependence of the type of diffusion on coarse-graining time. The results showed that, as coarse-graining time increases, the type of diffusion changes from superdiffusion ? subdiffusion ? normal diffusion. The change in diffusive properties over the observed timescale reflects the coexistence of local order and global disorder in the defect turbulence.

UR - http://www.scopus.com/inward/record.url?scp=85063715608&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85063715608&partnerID=8YFLogxK

U2 - 10.3390/fluids3040099

DO - 10.3390/fluids3040099

M3 - Article

AN - SCOPUS:85063715608

VL - 3

JO - Fluids

JF - Fluids

SN - 2311-5521

IS - 4

M1 - 99

ER -