"Multiresolutional-proper orthogonal" hybrid analysis on turbulent structures in open-channel complex geometry flows

Hitoshi Miyamoto, Tohru Kanda

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

We propose a hybrid expansion that consists of a multiresolution approximation (MRA) and a proper orthogonal decomposition (POD) to analyze turbulent flow structures in open-channel flows with complex geometries. The open-channel cavity flows are examined here and their velocity vectors are measured by using particle image velocimetry (PIV). In the first step of the hybrid expansion, the velocity time-series are classified into three distinct components using the MRA, i.e. pseudo-mean velocity, organized turbulence in a mixing shear layer, and incoherent turbulence. In the next step, these velocity components are decomposed by applying the POD. The principal components of the pseudo-mean velocity and the organized turbulence disclose the predominant flow characteristics, such as spatial structures of recirculating flows in the cavity and organized turbulent motions along the mixing shear layer, hysteretic behavior in modal time-series, and so forth. The results strongly support that the present hybrid analysis is effective for detecting spatiotemporal hierarchical structures in turbulent flows with complex geometries.

Original languageEnglish
Pages (from-to)297-310
Number of pages14
JournalInternational Journal of Wavelets, Multiresolution and Information Processing
Volume4
Issue number2
DOIs
Publication statusPublished - 2006 Jun
Externally publishedYes

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Geometry
Turbulence
Turbulent flow
Time series
Decomposition
Open channel flow
Flow structure
Velocity measurement

Keywords

  • Hybrid expansion
  • Open-channel cavity flow
  • Organized turbulence
  • Proper orthogonal decomposition
  • Wavelet transform

ASJC Scopus subject areas

  • Applied Mathematics
  • Information Systems
  • Signal Processing

Cite this

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title = "{"}Multiresolutional-proper orthogonal{"} hybrid analysis on turbulent structures in open-channel complex geometry flows",
abstract = "We propose a hybrid expansion that consists of a multiresolution approximation (MRA) and a proper orthogonal decomposition (POD) to analyze turbulent flow structures in open-channel flows with complex geometries. The open-channel cavity flows are examined here and their velocity vectors are measured by using particle image velocimetry (PIV). In the first step of the hybrid expansion, the velocity time-series are classified into three distinct components using the MRA, i.e. pseudo-mean velocity, organized turbulence in a mixing shear layer, and incoherent turbulence. In the next step, these velocity components are decomposed by applying the POD. The principal components of the pseudo-mean velocity and the organized turbulence disclose the predominant flow characteristics, such as spatial structures of recirculating flows in the cavity and organized turbulent motions along the mixing shear layer, hysteretic behavior in modal time-series, and so forth. The results strongly support that the present hybrid analysis is effective for detecting spatiotemporal hierarchical structures in turbulent flows with complex geometries.",
keywords = "Hybrid expansion, Open-channel cavity flow, Organized turbulence, Proper orthogonal decomposition, Wavelet transform",
author = "Hitoshi Miyamoto and Tohru Kanda",
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AU - Miyamoto, Hitoshi

AU - Kanda, Tohru

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N2 - We propose a hybrid expansion that consists of a multiresolution approximation (MRA) and a proper orthogonal decomposition (POD) to analyze turbulent flow structures in open-channel flows with complex geometries. The open-channel cavity flows are examined here and their velocity vectors are measured by using particle image velocimetry (PIV). In the first step of the hybrid expansion, the velocity time-series are classified into three distinct components using the MRA, i.e. pseudo-mean velocity, organized turbulence in a mixing shear layer, and incoherent turbulence. In the next step, these velocity components are decomposed by applying the POD. The principal components of the pseudo-mean velocity and the organized turbulence disclose the predominant flow characteristics, such as spatial structures of recirculating flows in the cavity and organized turbulent motions along the mixing shear layer, hysteretic behavior in modal time-series, and so forth. The results strongly support that the present hybrid analysis is effective for detecting spatiotemporal hierarchical structures in turbulent flows with complex geometries.

AB - We propose a hybrid expansion that consists of a multiresolution approximation (MRA) and a proper orthogonal decomposition (POD) to analyze turbulent flow structures in open-channel flows with complex geometries. The open-channel cavity flows are examined here and their velocity vectors are measured by using particle image velocimetry (PIV). In the first step of the hybrid expansion, the velocity time-series are classified into three distinct components using the MRA, i.e. pseudo-mean velocity, organized turbulence in a mixing shear layer, and incoherent turbulence. In the next step, these velocity components are decomposed by applying the POD. The principal components of the pseudo-mean velocity and the organized turbulence disclose the predominant flow characteristics, such as spatial structures of recirculating flows in the cavity and organized turbulent motions along the mixing shear layer, hysteretic behavior in modal time-series, and so forth. The results strongly support that the present hybrid analysis is effective for detecting spatiotemporal hierarchical structures in turbulent flows with complex geometries.

KW - Hybrid expansion

KW - Open-channel cavity flow

KW - Organized turbulence

KW - Proper orthogonal decomposition

KW - Wavelet transform

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