Large-eddy simulation of supercritical free-surface flow in an open-channel contraction

Adzic, Filipa, Stoesser, Thorsten, Liu, Yan and Xie, Zhihua ORCID: https://orcid.org/0000-0002-5180-8427 2022. Large-eddy simulation of supercritical free-surface flow in an open-channel contraction. Journal of Hydraulic Research 60 (4) , pp. 628-644. 10.1080/00221686.2022.2041496

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Abstract

Large-eddy simulations (LES) of supercritical flow in a straight-wall, open-channel contraction of 6° and contraction ratio of 2:1 are performed. The LES code solves the filtered Navier-Stokes equations for two-phase flows (water-air) and employs the level-set method. The simulation was validated by replicating a previously reported experiment. Contours of the time-averaged velocities indicate that the flow loses energy and momentum in the contracting channel. Further, secondary currents in the contraction are redistributing momentum and are responsible for local up-and down-flows. The turbulent kinetic energy reaches very high values at the entrance of the contraction, mainly contributed by the streamwise normal stress. The flow contains coherent turbulence structures which are responsible for carrying low-momentum from the bed and the water surface towards the channel centre. Flow deceleration results in significant turbulence anisotropy in the contracted section. It is shown that mainly pressure drag contributes to the energy loss in the contraction.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Advanced Research Computing @ Cardiff (ARCCA) Engineering
Additional Information:	This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Publisher:	Taylor and Francis
ISSN:	0022-1686
Date of First Compliant Deposit:	21 June 2022
Date of Acceptance:	3 February 2022
Last Modified:	01 Aug 2024 13:28
URI:	https://orca.cardiff.ac.uk/id/eprint/150592

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