An Experimental Study on Three-Dimensional Turbulent Structure in a Rectangular Open Channel Flow

Tominaga, Akira; Ezaki, Kazuhiro

doi:10.2208/jscej.1985.357_81

Cited by 14 publications

(1 citation statement)

References 9 publications

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“…2). Tominaga and Ezaki (1985) found a decreasing trend in the distribution of (v9 2 À w9 2 )=u 2 max for an aspect ratio of W/h ¼ 2 in the region z/h , 0 . 2, which is confirmed by Figure 7.…”

Section: Discussionmentioning

confidence: 83%

Cobble-bed concentrations and vegetated banks: effects on flow

Afzalimehr¹,

Bagheri²,

Gallichand³

et al. 2014

Proceedings of the Institution of Civil Engineers - Water Manag

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The effect of cobble concentration and vegetated banks on the mean flow and turbulence of streams has not yet been investigated. Cobble concentrations ranging from 10 to 30 cobbles/m 2 were tested by this study. In total, 27 velocity profiles were measured using an acoustic Doppler velocimeter (ADV) at a sampling frequency of 200 Hz. The results show that cobble concentration affects the mean velocity and turbulence intensity profiles close to the vegetated bank, especially near the bed, but does not influence the RS distribution. This experimental study reveals a Z-shaped Reynolds stress (RS) distribution near the vegetated bank without any negative values, but a convex distribution at the centre of flume with negative values near the water surface. Negative RS values are associated with dominant effects of the inward and outward events near the water surface. The effect of cobble concentration on the frequency of bursting events is not considerable, based on the quadrant analysis.

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Section: Discussionmentioning

confidence: 83%

Cobble-bed concentrations and vegetated banks: effects on flow

Afzalimehr¹,

Bagheri²,

Gallichand³

et al. 2014

Proceedings of the Institution of Civil Engineers - Water Manag

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Importance of vegetation in riverbank resilience: An experimental approach

Barman,

Kumar

2024

Earth Surf Processes Landf

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Floodplain (FP) vegetation determines the flow structures in river channels based on its shape, type, spacing and root‐soil binding capacity. The present study focuses on experimental approach to understand the role of FP vegetation in determining the flow patterns and morphological changes in the channels. Flow properties like streamwise and transverse velocity, along with secondary flow and turbulent kinetic energy, were compared between rectangular and compound channels considering partial vegetation cover. The presence and absence of dip phenomenon in the main channel (MC) of compound and rectangular channel respectively suggest that the dip phenomenon is influenced by both vegetation emergence in FPs and differential cross‐sectional depths of compound channels. The secondary flow direction in the slopes and MC of compound channel is towards the FP region which is opposite to that observed in rectangular channel where secondary flow is towards MC showing the effect of non‐uniform cross‐section of compound channels. The morphological changes were analysed by performing experiments in unsymmetrical erodible riverbank channels with bankfull condition considering artificial rigid FP vegetation (Phragmites karka) and naturally growing flexible vegetation (Oryza sativa). After more than 24 h of continuous experimental runs, the O. sativa remains intact in the soil because of development of strong root‐soil bond whereas; all the P. karka gets uprooted. The channel cross‐section in the downstream channel becomes almost uniform for P. karka, whereas differential cross‐sectional height is observed for O. sativa. This study shows that along with the shapes and size of vegetation, root‐soil binding capacity also determines the morphological changes in river channels. Furthermore, it also shows the importance of growing vegetation in the laboratory to properly simulate vegetation observed in river channels.

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