Dynamic structuring and mixing efficiency in rapidly rotating shear layers

Bernard J. Geurts; Darryl D. Holm

doi:10.1007/978-1-4020-5152-2_29

Dynamic structuring and mixing efficiency in rapidly rotating shear layers

Bernard J. Geurts, Darryl D. Holm

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › Academic › peer-review

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Abstract

Flow evolution in a rotating mixing layer is investigated using direct and large-eddy simulation. The mixing layer rotates about a fixed vertical axis perpendicular to the plane of its mean initial shear. The rotating mixing layer forms oscillatory large-scale columnar structures and rapid horizontal flow-reversals. The frequency of these oscillations varies approximately inversely with the Rossby number, $Ro$. At low $Ro$ vertical mixing of a passive scalar is strongly reduced. This is quantified by investigating the evolution of level-sets of the scalar field. The surface-area of the level-sets remains virtually constant even at modest rotation rates. More localized motions are less affected by rotation and yield comparatively high levels of surface-wrinkling. Rotation effects are accurately predicted in large-eddy simulations that involve the dynamic eddy-viscosity model or the LANS-$\alpha$ or Leray regularization models. The small-scale variability is best preserved when using the LANS-$\alpha$ formulation.

Original language	English
Title of host publication	Direct and Large-Eddy Simulation VI
Editors	Eric Lamballais, Rainer Friedrich, Bernard J. Geurts, Olivier Métais
Place of Publication	Dordrecht
Publisher	Springer
Pages	249-256
Number of pages	8
ISBN (Electronic)	978-1-4020-5152-4
ISBN (Print)	978-1-4020-4909-5
DOIs	https://doi.org/10.1007/978-1-4020-5152-2_29
Publication status	Published - Oct 2006
Event	6th ERCOFTAC Workshop on Direct and Large-Eddy Simulation VI, DLES 2005 - University of Poitiers, Poitiers, France Duration: 12 Sep 2005 → 14 Sep 2005 Conference number: 6

Publication series

Name	ERCOFTAC series
Publisher	Springer
Volume	10
ISSN (Print)	1382-4309
ISSN (Electronic)	2215-1826

Conference

Conference	6th ERCOFTAC Workshop on Direct and Large-Eddy Simulation VI, DLES 2005
Abbreviated title	DLES
Country	France
City	Poitiers
Period	12/09/05 → 14/09/05

Keywords

Direct numerical simulation
Rotation rate
Passive scalar
Momentum thickness
Rossby number

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@inproceedings{295f848976aa44c89623d9414ec1fc4f,

title = "Dynamic structuring and mixing efficiency in rapidly rotating shear layers",

abstract = "Flow evolution in a rotating mixing layer is investigated using direct and large-eddy simulation. The mixing layer rotates about a fixed vertical axis perpendicular to the plane of its mean initial shear. The rotating mixing layer forms oscillatory large-scale columnar structures and rapid horizontal flow-reversals. The frequency of these oscillations varies approximately inversely with the Rossby number, $Ro$. At low $Ro$ vertical mixing of a passive scalar is strongly reduced. This is quantified by investigating the evolution of level-sets of the scalar field. The surface-area of the level-sets remains virtually constant even at modest rotation rates. More localized motions are less affected by rotation and yield comparatively high levels of surface-wrinkling. Rotation effects are accurately predicted in large-eddy simulations that involve the dynamic eddy-viscosity model or the LANS-$\alpha$ or Leray regularization models. The small-scale variability is best preserved when using the LANS-$\alpha$ formulation.",

keywords = "Direct numerical simulation, Rotation rate, Passive scalar, Momentum thickness, Rossby number",

author = "Geurts, {Bernard J.} and Holm, {Darryl D.}",

year = "2006",

month = oct,

doi = "10.1007/978-1-4020-5152-2_29",

language = "English",

isbn = "978-1-4020-4909-5",

series = "ERCOFTAC series",

publisher = "Springer",

pages = "249--256",

editor = "Eric Lamballais and Rainer Friedrich and Geurts, {Bernard J.} and Olivier M{\'e}tais",

booktitle = "Direct and Large-Eddy Simulation VI",

note = "6th ERCOFTAC Workshop on Direct and Large-Eddy Simulation VI, DLES 2005, DLES ; Conference date: 12-09-2005 Through 14-09-2005",

}

Geurts, BJ & Holm, DD 2006, Dynamic structuring and mixing efficiency in rapidly rotating shear layers. in E Lamballais, R Friedrich, BJ Geurts & O Métais (eds), Direct and Large-Eddy Simulation VI. ERCOFTAC series, vol. 10, Springer, Dordrecht, pp. 249-256, 6th ERCOFTAC Workshop on Direct and Large-Eddy Simulation VI, DLES 2005, Poitiers, France, 12/09/05. https://doi.org/10.1007/978-1-4020-5152-2_29

Dynamic structuring and mixing efficiency in rapidly rotating shear layers. / Geurts, Bernard J.; Holm, Darryl D.

Direct and Large-Eddy Simulation VI. ed. / Eric Lamballais; Rainer Friedrich; Bernard J. Geurts; Olivier Métais. Dordrecht : Springer, 2006. p. 249-256 (ERCOFTAC series; Vol. 10).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › Academic › peer-review

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AU - Geurts, Bernard J.

AU - Holm, Darryl D.

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N2 - Flow evolution in a rotating mixing layer is investigated using direct and large-eddy simulation. The mixing layer rotates about a fixed vertical axis perpendicular to the plane of its mean initial shear. The rotating mixing layer forms oscillatory large-scale columnar structures and rapid horizontal flow-reversals. The frequency of these oscillations varies approximately inversely with the Rossby number, $Ro$. At low $Ro$ vertical mixing of a passive scalar is strongly reduced. This is quantified by investigating the evolution of level-sets of the scalar field. The surface-area of the level-sets remains virtually constant even at modest rotation rates. More localized motions are less affected by rotation and yield comparatively high levels of surface-wrinkling. Rotation effects are accurately predicted in large-eddy simulations that involve the dynamic eddy-viscosity model or the LANS-$\alpha$ or Leray regularization models. The small-scale variability is best preserved when using the LANS-$\alpha$ formulation.

AB - Flow evolution in a rotating mixing layer is investigated using direct and large-eddy simulation. The mixing layer rotates about a fixed vertical axis perpendicular to the plane of its mean initial shear. The rotating mixing layer forms oscillatory large-scale columnar structures and rapid horizontal flow-reversals. The frequency of these oscillations varies approximately inversely with the Rossby number, $Ro$. At low $Ro$ vertical mixing of a passive scalar is strongly reduced. This is quantified by investigating the evolution of level-sets of the scalar field. The surface-area of the level-sets remains virtually constant even at modest rotation rates. More localized motions are less affected by rotation and yield comparatively high levels of surface-wrinkling. Rotation effects are accurately predicted in large-eddy simulations that involve the dynamic eddy-viscosity model or the LANS-$\alpha$ or Leray regularization models. The small-scale variability is best preserved when using the LANS-$\alpha$ formulation.

KW - Direct numerical simulation

KW - Rotation rate

KW - Passive scalar

KW - Momentum thickness

KW - Rossby number

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BT - Direct and Large-Eddy Simulation VI

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A2 - Métais, Olivier

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