Emergence of Kelvin-Helmholtz instabilities in shallow mixing layers: An experimental study

S. Proust; C. Berni; V. I. Nikora

Emergence of Kelvin-Helmholtz instabilities in shallow mixing layers: An experimental study

S. Proust, C. Berni, V. I. Nikora

Engineering

Research output: Chapter in Book/Report/Conference proceeding › Published conference contribution

Abstract

Free-surface shallow mixing layers behind a splitter plate were studied in a flume of rectangular cross-section consisting of a bed and sidewalls made of glass. The focus is on the effects on the emergence of horizontal Kelvin-Helmholtz-type coherent structures (KHCSs) of vertical flow confinement (i.e., flow depth) and dimensionless velocity shear λ=(U_X2 - U_X1) / (U_X2 + U_X1) where U_X1 and U_X2 are two flow velocities characterizing the low-speed stream and high-speed stream, respectively. Two flow depths were tested, with the λ-value at the flume entrance varying between 0.1 to 0.8, with a threshold value λ = 0.3 needed for the emergence of KHCSs in compound open-channel flows being inside this range. This paper reports new data that provide a better insight in the interplay between the constraining effect of flow depth, damping effect of three-dimensional bed-induced turbulence, and triggering effect of dimensionless shear on the formation of KHCSs.

Original language	English
Title of host publication	River Flow 2020 - Proceedings of the 10th Conference on Fluvial Hydraulics
Editors	Wim Uijttewaal, Mario J. Franca, Daniel Valero, Victor Chavarrias, Claudia Ylla Arbos, Ralph Schielen, Ralph Schielen, Alessandra Crosato
Publisher	CRC Press/Balkema
Pages	76-83
Number of pages	8
ISBN (Electronic)	9780367627737
Publication status	Published - 2020
Event	10th Conference on Fluvial Hydraulics, River Flow 2020 - Virtual, Online, Netherlands Duration: 7 Jul 2020 → 10 Jul 2020

Conference

Conference	10th Conference on Fluvial Hydraulics, River Flow 2020
Country/Territory	Netherlands
City	Virtual, Online
Period	7/07/20 → 10/07/20

Keywords

Coherent structures
Shallow shear flows
Shear layer turbulence

Cite this

Emergence of Kelvin-Helmholtz instabilities in shallow mixing layers : An experimental study. / Proust, S.; Berni, C.; Nikora, V. I.

River Flow 2020 - Proceedings of the 10th Conference on Fluvial Hydraulics. ed. / Wim Uijttewaal; Mario J. Franca; Daniel Valero; Victor Chavarrias; Claudia Ylla Arbos; Ralph Schielen; Ralph Schielen; Alessandra Crosato. CRC Press/Balkema, 2020. p. 76-83.

Research output: Chapter in Book/Report/Conference proceeding › Published conference contribution

Proust, S, Berni, C & Nikora, VI 2020, Emergence of Kelvin-Helmholtz instabilities in shallow mixing layers: An experimental study. in W Uijttewaal, MJ Franca, D Valero, V Chavarrias, CY Arbos, R Schielen, R Schielen & A Crosato (eds), River Flow 2020 - Proceedings of the 10th Conference on Fluvial Hydraulics. CRC Press/Balkema, pp. 76-83, 10th Conference on Fluvial Hydraulics, River Flow 2020, Virtual, Online, Netherlands, 7/07/20.

Proust, S. ; Berni, C. ; Nikora, V. I. / Emergence of Kelvin-Helmholtz instabilities in shallow mixing layers : An experimental study. River Flow 2020 - Proceedings of the 10th Conference on Fluvial Hydraulics. editor / Wim Uijttewaal ; Mario J. Franca ; Daniel Valero ; Victor Chavarrias ; Claudia Ylla Arbos ; Ralph Schielen ; Ralph Schielen ; Alessandra Crosato. CRC Press/Balkema, 2020. pp. 76-83

@inproceedings{0b7c704dffe04c29ad345659e2344492,

title = "Emergence of Kelvin-Helmholtz instabilities in shallow mixing layers: An experimental study",

abstract = "Free-surface shallow mixing layers behind a splitter plate were studied in a flume of rectangular cross-section consisting of a bed and sidewalls made of glass. The focus is on the effects on the emergence of horizontal Kelvin-Helmholtz-type coherent structures (KHCSs) of vertical flow confinement (i.e., flow depth) and dimensionless velocity shear λ=(UX2 - UX1) / (UX2 + UX1) where UX1 and UX2 are two flow velocities characterizing the low-speed stream and high-speed stream, respectively. Two flow depths were tested, with the λ-value at the flume entrance varying between 0.1 to 0.8, with a threshold value λ = 0.3 needed for the emergence of KHCSs in compound open-channel flows being inside this range. This paper reports new data that provide a better insight in the interplay between the constraining effect of flow depth, damping effect of three-dimensional bed-induced turbulence, and triggering effect of dimensionless shear on the formation of KHCSs.",

keywords = "Coherent structures, Shallow shear flows, Shear layer turbulence",

author = "S. Proust and C. Berni and Nikora, {V. I.}",

note = "Publisher Copyright: {\textcopyright} 2020 Taylor & Francis Group, London; 10th Conference on Fluvial Hydraulics, River Flow 2020 ; Conference date: 07-07-2020 Through 10-07-2020",

year = "2020",

language = "English",

pages = "76--83",

editor = "Wim Uijttewaal and Franca, {Mario J.} and Daniel Valero and Victor Chavarrias and Arbos, {Claudia Ylla} and Ralph Schielen and Ralph Schielen and Alessandra Crosato",

booktitle = "River Flow 2020 - Proceedings of the 10th Conference on Fluvial Hydraulics",

publisher = "CRC Press/Balkema",

}

TY - GEN

T1 - Emergence of Kelvin-Helmholtz instabilities in shallow mixing layers

T2 - 10th Conference on Fluvial Hydraulics, River Flow 2020

AU - Proust, S.

AU - Berni, C.

AU - Nikora, V. I.

PY - 2020

Y1 - 2020

N2 - Free-surface shallow mixing layers behind a splitter plate were studied in a flume of rectangular cross-section consisting of a bed and sidewalls made of glass. The focus is on the effects on the emergence of horizontal Kelvin-Helmholtz-type coherent structures (KHCSs) of vertical flow confinement (i.e., flow depth) and dimensionless velocity shear λ=(UX2 - UX1) / (UX2 + UX1) where UX1 and UX2 are two flow velocities characterizing the low-speed stream and high-speed stream, respectively. Two flow depths were tested, with the λ-value at the flume entrance varying between 0.1 to 0.8, with a threshold value λ = 0.3 needed for the emergence of KHCSs in compound open-channel flows being inside this range. This paper reports new data that provide a better insight in the interplay between the constraining effect of flow depth, damping effect of three-dimensional bed-induced turbulence, and triggering effect of dimensionless shear on the formation of KHCSs.

AB - Free-surface shallow mixing layers behind a splitter plate were studied in a flume of rectangular cross-section consisting of a bed and sidewalls made of glass. The focus is on the effects on the emergence of horizontal Kelvin-Helmholtz-type coherent structures (KHCSs) of vertical flow confinement (i.e., flow depth) and dimensionless velocity shear λ=(UX2 - UX1) / (UX2 + UX1) where UX1 and UX2 are two flow velocities characterizing the low-speed stream and high-speed stream, respectively. Two flow depths were tested, with the λ-value at the flume entrance varying between 0.1 to 0.8, with a threshold value λ = 0.3 needed for the emergence of KHCSs in compound open-channel flows being inside this range. This paper reports new data that provide a better insight in the interplay between the constraining effect of flow depth, damping effect of three-dimensional bed-induced turbulence, and triggering effect of dimensionless shear on the formation of KHCSs.

KW - Coherent structures

KW - Shallow shear flows

KW - Shear layer turbulence

UR - http://www.scopus.com/inward/record.url?scp=85117366618&partnerID=8YFLogxK

M3 - Published conference contribution

AN - SCOPUS:85117366618

SP - 76

EP - 83

BT - River Flow 2020 - Proceedings of the 10th Conference on Fluvial Hydraulics

A2 - Uijttewaal, Wim

A2 - Franca, Mario J.

A2 - Valero, Daniel

A2 - Chavarrias, Victor

A2 - Arbos, Claudia Ylla

A2 - Schielen, Ralph

A2 - Crosato, Alessandra

PB - CRC Press/Balkema

Y2 - 7 July 2020 through 10 July 2020

ER -

Emergence of Kelvin-Helmholtz instabilities in shallow mixing layers: An experimental study

Abstract

Conference

Keywords

Other files and links

Fingerprint

Cite this