Details

Autor(en) / Beteiligte

• Adzic, Filipa
• Stoesser, Thorsten
• Liu, Yan
• Xie, Zhihua

Titel

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

Ist Teil von

• Journal of hydraulic research, 2022-07, Vol.60 (4), p.628-644

Ort / Verlag

Madrid: Taylor & Francis

Erscheinungsjahr

2022

Quelle

Taylor & Francis

Beschreibungen/Notizen

• 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.