3D Numerical modelling of flow divisions at open channel junctions with or without vegetation

Li, Chi Wai; Zeng, Cheng

doi:10.1016/j.advwatres.2008.09.005

Cited by 47 publications

(15 citation statements)

References 18 publications

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“…Several studies of vegetated flow have considered the effects of this characteristic in continuous vegetation beds (Huai et al, 2009;Järvelä, 2005;Li and Zeng, 2009;Stephan and Gutknecht, 2002). White and Nepf (2007) found relationships between vegetation stem density and turbulence levels for continuous, homogeneous distributions of both submerged and emergent vegetation.…”

Section: Introductionmentioning

confidence: 98%

Flow and turbulence in vegetation in a channel

Montakhab¹,

Yusuf²,

Folkard³

2015

Proceedings of the Institution of Civil Engineers - Water Manag

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The distribution of aquatic vegetation within conveyance channels plays a key role in the determination of their hydraulic characteristics, especially where the vegetation is patchy, as is commonly found in nature. This paper reports the results of a laboratory flume study on flow and turbulence conditions caused by patches of the emergent rush Lepironia articulata. Acoustic Doppler velocimeter measurements were taken within and downstream of singleand multiple-patch configurations of this plant, and the effects of varying incident flow rate (0 . 16-0 . 32 m/s) and stem-scale porosity (12-4% solid volume fraction) were investigated. The results showed that flow encountering a single patch formed a turbulent wake downstream of the vegetation. Within this wake, the Reynolds stress increased downstream initially, and then decayed. When a second patch was positioned within the region of maximum Reynolds stress, the Reynolds stress decreased by between 25 and 50%. The amount of this reduction was dependent on the porosity of the vegetation and the flow rate, and was greater at lower flow rates and porosities. These changes in turbulent flow fields around patches of emergent vegetation are likely to be important in determining sediment budgets in their vicinity.

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Section: Introductionmentioning

confidence: 98%

Flow and turbulence in vegetation in a channel

Montakhab¹,

Yusuf²,

Folkard³

2015

Proceedings of the Institution of Civil Engineers - Water Manag

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“…Shettar andMurthy 1996, Khan et al 2000) and 3D models (e.g. Neary et al 1999, Ramamurthy et al 2007, Li and Zeng 2009, 2010 were applied to simulate subcritical dividing flows. However, junction flow may have a transient behaviour with a change from the sub-to the supercritical regime, or vice versa (Mignot et al 2006, Soares-Frazão et al 2008.…”

Section: Introductionmentioning

confidence: 99%

Division of critical flow at three-branch open-channel intersection

Abderrezzak

Lewicki

Paquier³

et al. 2011

Journal of Hydraulic Research

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International audienceAn experimental study of the characteristics of dividing critical flows in a 90° open-channel junction formed by three horizontal equal-width branches is presented, conducted for various inflow discharges and downstream boundary conditions. Outflow discharges and flow depths were also measured. Four main flow patterns are identified considering the location and length of the hydraulic jumps that develop across the main and lateral channels. A relationship between the discharge division ratio and the tailwater Froude number is found, reproducing well the experimental data. Practical applications of this relationship include the design of open channel and pipe networks and one-dimensional numerical modelling of flood propagation in urban areas. The study shows also that a two-dimensional depth-averaged numerical model hardly gives better predictions of the discharge ratios because of the presence of three-dimensional features at the junction

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“…Our global initial angle vector is U 0 . Use (28) to assemble the initial gradient vector g 0 . Delete the entries that correspond to fixed points.…”

Section: Methodsmentioning

confidence: 99%

“…Kubrak et al [26] extend the method developed by Kutija and Hong [18] for large deflections. Li an Xie [27] build off work involving stiff vegetation by Li and Zeng [28], add a thin plate of ''foliage'' to the stems and use a 3D LES scheme with a Smagorinsky closure model. They do not completely couple these models.…”

Section: Motivationmentioning

confidence: 99%