Eulerian and Lagrangian statistics in stably stratified turbulent channel flows

Kyongmin Yeo, Byung Gu Kim, Chang Hoon Lee

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Using direct numerical simulation, we investigate the Eulerian and Lagrangian characteristics of the near-wall turbulence under stable stratification. In the near-wall region, large-scale motions are suppressed by stable stratification, while small-scale motions are enhanced, which leads to the increase of intermittency. It is shown that the modification of the Reynolds shear stress is caused by the increased intermittency and anisotropy. Investigation of acceleration and vorticity reveals that the length scales and timescales of the near-wall coherent vortices are reduced by stratification. The role of baroclinic torque around the near-wall turbulent structures is also discussed. The Lagrangian statistics indicate that the scaled dispersion in the streamwise direction remains unchanged, while those in the spanwise as well as in the wall-normal direction are suppressed by stratification.

Original languageEnglish
Pages (from-to)1-26
Number of pages26
JournalJournal of Turbulence
Volume10
DOIs
Publication statusPublished - 2009 Aug 25

Fingerprint

Direct numerical simulation
channel flow
Channel flow
Vorticity
Shear stress
stratification
Vortex flow
Anisotropy
Turbulence
Torque
Statistics
statistics
intermittency
Reynolds stress
direct numerical simulation
vorticity
shear stress
torque
turbulence
vortices

All Science Journal Classification (ASJC) codes

  • Computational Mechanics
  • Condensed Matter Physics
  • Mechanics of Materials
  • Physics and Astronomy(all)

Cite this

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Eulerian and Lagrangian statistics in stably stratified turbulent channel flows. / Yeo, Kyongmin; Kim, Byung Gu; Lee, Chang Hoon.

In: Journal of Turbulence, Vol. 10, 25.08.2009, p. 1-26.

Research output: Contribution to journalArticle

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AB - Using direct numerical simulation, we investigate the Eulerian and Lagrangian characteristics of the near-wall turbulence under stable stratification. In the near-wall region, large-scale motions are suppressed by stable stratification, while small-scale motions are enhanced, which leads to the increase of intermittency. It is shown that the modification of the Reynolds shear stress is caused by the increased intermittency and anisotropy. Investigation of acceleration and vorticity reveals that the length scales and timescales of the near-wall coherent vortices are reduced by stratification. The role of baroclinic torque around the near-wall turbulent structures is also discussed. The Lagrangian statistics indicate that the scaled dispersion in the streamwise direction remains unchanged, while those in the spanwise as well as in the wall-normal direction are suppressed by stratification.

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