Turbulent mixing in a rotating, stratified fluid

Yign Noh, Robert R. Long

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

An experimental study was carried out to investigate the effect of rotation on turbulent mixing in a stratified fluid when the turbulence in the mixed layer is generated by an oscillating grid. Two types of experiments were carried out: one of them is concerned with the deepening of the upper mixed layer in a stable, two-fluid system, and the other deals with the interaction between a stabilizing buoyancy flux and turbulence. In the first type of experiments, it was found that rotation suppresses entrainment at larger Rossby numbers. As the Rossby number becomes smaller (Ro<0.1), the entrainment rate increases with rotation-the onset of this phenomenon, however, was found to coincide with the appearance of coherent vortices within the mixed layer. The radiation of energy from the mixed layer to the lower non-turbulent layer was found to occur and the magnitude of the energy flux was found to be increased with the rotational frequency. It was also observed that vortices are generated, rather abruptly, in the lower layer as the mixed layer deepens. In the second set of experiments a quasi-steady mixed layer was found to develop of which the thickness varies with rotation in a fashion that is consistent with the result of the first experiment. Also the rotation was found to delay the formation of a pycnocline.

Original languageEnglish
Pages (from-to)125-143
Number of pages19
JournalGeophysical & Astrophysical Fluid Dynamics
Volume53
Issue number3
DOIs
Publication statusPublished - 1990 Jul 1

Fingerprint

stratified fluid
turbulent mixing
mixed layer
Fluids
fluids
Rossby number
Vortex flow
Turbulence
entrainment
Experiments
vortex
Fluxes
experiment
turbulence
Buoyancy
pycnocline
vortices
energy flux
buoyancy
experimental study

All Science Journal Classification (ASJC) codes

  • Computational Mechanics
  • Astronomy and Astrophysics
  • Geophysics
  • Mechanics of Materials
  • Geochemistry and Petrology

Cite this

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abstract = "An experimental study was carried out to investigate the effect of rotation on turbulent mixing in a stratified fluid when the turbulence in the mixed layer is generated by an oscillating grid. Two types of experiments were carried out: one of them is concerned with the deepening of the upper mixed layer in a stable, two-fluid system, and the other deals with the interaction between a stabilizing buoyancy flux and turbulence. In the first type of experiments, it was found that rotation suppresses entrainment at larger Rossby numbers. As the Rossby number becomes smaller (Ro<0.1), the entrainment rate increases with rotation-the onset of this phenomenon, however, was found to coincide with the appearance of coherent vortices within the mixed layer. The radiation of energy from the mixed layer to the lower non-turbulent layer was found to occur and the magnitude of the energy flux was found to be increased with the rotational frequency. It was also observed that vortices are generated, rather abruptly, in the lower layer as the mixed layer deepens. In the second set of experiments a quasi-steady mixed layer was found to develop of which the thickness varies with rotation in a fashion that is consistent with the result of the first experiment. Also the rotation was found to delay the formation of a pycnocline.",
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Turbulent mixing in a rotating, stratified fluid. / Noh, Yign; Long, Robert R.

In: Geophysical & Astrophysical Fluid Dynamics, Vol. 53, No. 3, 01.07.1990, p. 125-143.

Research output: Contribution to journalArticle

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