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Communication Dans Un Congrès Année : 2020

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

Résumé

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 λt = 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.
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Dates et versions

hal-03130140 , version 1 (03-02-2021)

Identifiants

  • HAL Id : hal-03130140 , version 1

Citer

Sébastien Proust, Céline Berni, V.I. Nikora. Emergence of Kelvin-Helmholtz instabilities in shallow mixing layers: An experimental study. River Flow 2020, Jul 2020, Delft, Netherlands. pp.8. ⟨hal-03130140⟩
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