Active and passive in-plane wall fluctuations in turbulent channel flows

T. I. Jozsa; E. Balaras; M. Kashtalyan; A. G. L. Borthwick; I. M. Viola

doi:10.1017/jfm.2019.145

Active and passive in-plane wall fluctuations in turbulent channel flows

T. I. Jozsa (Corresponding Author), E. Balaras, M. Kashtalyan, A. G. L. Borthwick, I. M. Viola

Research output: Contribution to journal › Article › peer-review

25 Citations (Scopus)

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Abstract

Compliant walls offer the tantalising possibility of passive flow control. This paper examines the mechanics of compliant surfaces driven by wall shear stresses, with solely in-plane velocity response. We present direct numerical simulations of turbulent channel flows at low (Reτ ≈ 180) and intermediate (Reτ ≈ 1000) Reynolds numbers. Inplane spanwise and streamwise active controls proposed by Choi et al. (1994, Journal of Fluid Mechanics 262: 75-110) are revisited in order to characterise beneficial wall fluctuations. An analytical framework is then used to map the parameter space of the proposed compliant surfaces. The direct numerical simulations show that large-scale passive streamwise wall fluctuations can reduce friction drag by at least 3.7±1%, whereas even small-scale passive spanwise wall motions lead to considerable drag penalty. It is found that a well-designed compliant wall can theoretically exploit the drag reduction mechanism of an active control; this may help advance the development of practical active and passive control strategies for turbulent friction drag reduction.

Original language	English
Pages (from-to)	689-720
Number of pages	32
Journal	Journal of Fluid Mechanics
Volume	866
Early online date	18 Mar 2019
DOIs	https://doi.org/10.1017/jfm.2019.145
Publication status	Published - 10 May 2019

Bibliographical note

The authors are grateful to AkzoNobel’s Marine Coatings business (International
Paint Ltd) and the Energy Technology Partnership [ETP106] for financial support. DNS computations were carried out on the ARCHER UK National Supercomputing Service (http://www.archer.ac.uk).

Keywords

turbulent boundary layers
flow control
drag reduction
boundary layer control
drag-reduction
boundary-layer
large-scale
deformation
hydrodynamic stability
direct numerical-simulation
skin-friction
viscous drag
compliant surface
opposition control

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10.1017/jfm.2019.145Licence: CC BY-NC-SA

Active and passive in-plane wall fluctuations in turbulent channel flows
This is an Open Access article, distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike licence (http://creativecommons.org/licenses/by-nc-sa/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the same Creative Commons licence is included and the original work is properly cited. The written permission of Cambridge University Press must be obtained for commercial re-use.
Final published version, 802 KBLicence: CC BY-NC-SA

Cite this

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title = "Active and passive in-plane wall fluctuations in turbulent channel flows",

abstract = "Compliant walls offer the tantalising possibility of passive flow control. This paper examines the mechanics of compliant surfaces driven by wall shear stresses, with solely in-plane velocity response. We present direct numerical simulations of turbulent channel flows at low (Reτ ≈ 180) and intermediate (Reτ ≈ 1000) Reynolds numbers. Inplane spanwise and streamwise active controls proposed by Choi et al. (1994, Journal of Fluid Mechanics 262: 75-110) are revisited in order to characterise beneficial wall fluctuations. An analytical framework is then used to map the parameter space of the proposed compliant surfaces. The direct numerical simulations show that large-scale passive streamwise wall fluctuations can reduce friction drag by at least 3.7±1%, whereas even small-scale passive spanwise wall motions lead to considerable drag penalty. It is found that a well-designed compliant wall can theoretically exploit the drag reduction mechanism of an active control; this may help advance the development of practical active and passive control strategies for turbulent friction drag reduction.",

keywords = "turbulent boundary layers, flow control, drag reduction, boundary layer control, drag-reduction, boundary-layer, large-scale, deformation, hydrodynamic stability, direct numerical-simulation, skin-friction, viscous drag, compliant surface, opposition control",

author = "Jozsa, {T. I.} and E. Balaras and M. Kashtalyan and Borthwick, {A. G. L.} and Viola, {I. M.}",

note = "The authors are grateful to AkzoNobel{\textquoteright}s Marine Coatings business (International Paint Ltd) and the Energy Technology Partnership [ETP106] for financial support. DNS computations were carried out on the ARCHER UK National Supercomputing Service (http://www.archer.ac.uk).",

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AU - Balaras, E.

AU - Kashtalyan, M.

AU - Borthwick, A. G. L.

AU - Viola, I. M.

N1 - The authors are grateful to AkzoNobel’s Marine Coatings business (International Paint Ltd) and the Energy Technology Partnership [ETP106] for financial support. DNS computations were carried out on the ARCHER UK National Supercomputing Service (http://www.archer.ac.uk).

PY - 2019/5/10

Y1 - 2019/5/10

N2 - Compliant walls offer the tantalising possibility of passive flow control. This paper examines the mechanics of compliant surfaces driven by wall shear stresses, with solely in-plane velocity response. We present direct numerical simulations of turbulent channel flows at low (Reτ ≈ 180) and intermediate (Reτ ≈ 1000) Reynolds numbers. Inplane spanwise and streamwise active controls proposed by Choi et al. (1994, Journal of Fluid Mechanics 262: 75-110) are revisited in order to characterise beneficial wall fluctuations. An analytical framework is then used to map the parameter space of the proposed compliant surfaces. The direct numerical simulations show that large-scale passive streamwise wall fluctuations can reduce friction drag by at least 3.7±1%, whereas even small-scale passive spanwise wall motions lead to considerable drag penalty. It is found that a well-designed compliant wall can theoretically exploit the drag reduction mechanism of an active control; this may help advance the development of practical active and passive control strategies for turbulent friction drag reduction.

AB - Compliant walls offer the tantalising possibility of passive flow control. This paper examines the mechanics of compliant surfaces driven by wall shear stresses, with solely in-plane velocity response. We present direct numerical simulations of turbulent channel flows at low (Reτ ≈ 180) and intermediate (Reτ ≈ 1000) Reynolds numbers. Inplane spanwise and streamwise active controls proposed by Choi et al. (1994, Journal of Fluid Mechanics 262: 75-110) are revisited in order to characterise beneficial wall fluctuations. An analytical framework is then used to map the parameter space of the proposed compliant surfaces. The direct numerical simulations show that large-scale passive streamwise wall fluctuations can reduce friction drag by at least 3.7±1%, whereas even small-scale passive spanwise wall motions lead to considerable drag penalty. It is found that a well-designed compliant wall can theoretically exploit the drag reduction mechanism of an active control; this may help advance the development of practical active and passive control strategies for turbulent friction drag reduction.

KW - turbulent boundary layers

KW - flow control

KW - drag reduction

KW - boundary layer control

KW - drag-reduction

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KW - large-scale

KW - deformation

KW - hydrodynamic stability

KW - direct numerical-simulation

KW - skin-friction

KW - viscous drag

KW - compliant surface

KW - opposition control

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UR - http://www.mendeley.com/research/active-passive-inplane-wall-fluctuations-turbulent-channel-flows

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EP - 720

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JF - Journal of Fluid Mechanics

ER -

Active and passive in-plane wall fluctuations in turbulent channel flows

Abstract

Bibliographical note

Keywords

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Maria Kashtalyan

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Active and passive in-plane wall fluctuations in turbulent channel flows

Abstract

Bibliographical note

Keywords

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Fingerprint

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Maria Kashtalyan

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