Shear Stress in Smooth Rectangular Open-Channel Flows

Guo, Junke; Juliën, Pierre Y.

doi:10.1061/(asce)0733-9429(2005)131:1(30)

Cited by 149 publications

(53 citation statements)

References 23 publications

(26 reference statements)

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“…where A is a constant (A = 2.5), Uf is the frictional velocity, z' − z1 is the distance between the measurement location and the theoretical bed surface level, is Nikuradse's equivalent sand grain roughness [34]. The average value of , representative of the average roughness across the main channel, reduces from 23 mm to 12 mm, for low to high vegetation density.…”

Section: Bed-shear Stressesmentioning

confidence: 99%

Flow Hydrodynamics across Open Channel Flows with Riparian Zones: Implications for Riverbank Stability

Valyrakis

Williams

2017

Water

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Riverbank vegetation is of high importance both for preserving the form (morphology) and function (ecology) of natural river systems. Revegetation of riverbanks is commonly used as a means of stream rehabilitation and management of bank instability and erosion. In this experimental study, the effect of different riverbank vegetation densities on flow hydrodynamics across the channel, including the riparian zone, are reported and discussed. The configuration of vegetation elements follows either linear or staggered arrangements as vegetation density is progressively increased, within a representative range of vegetation densities found in nature. Hydrodynamic measurements including mean streamwise velocity and turbulent intensity flow profiles are recorded via acoustic Doppler velocimetry (ADV)-both at the main channel and within the riverbank. These results show that for the main channel and the toe of riverbank, turbulence intensity for the low densities (λ ≈ 0 to 0.12 m −1 ) can increase up to 40% compared the case of high densities (λ = 0.94 to 1.9 m −1 ). Further analysis of these data allowed the estimation of bed-shear stresses, demonstrating 86% and 71% increase at the main channel and near the toe region, for increasing densities (λ = 0 to 1.9 m −1 ). Quantifying these hydrodynamic effects is important for assessing the contribution of physically representative ranges of riparian vegetation densities on hydrogeomorphologic feedback.

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Section: Bed-shear Stressesmentioning

confidence: 99%

Flow Hydrodynamics across Open Channel Flows with Riparian Zones: Implications for Riverbank Stability

Valyrakis

Williams

2017

Water

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“…Flow partitioning theory has been widely used in open channel flows by researchers such as Keulegan (1938), Einstein (1942), Yang and Lim (1997), Chien and Wan (1999), Guo and Julien (2005). Several mathematical treatments have been proposed to divide the cross section of a rectangular or trapezoidal channel into subsections (!!!…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Flow Division in a Smooth Circular Culvert

Han¹,

Qiu²,

Liu³

et al. 2017

Proceedings of the 2017 International Conference on Manufacturing Engineering and Intelligent Materials (ICMEIM 2017)

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Abstract:The idea of partitioning the flow has been widely used by hydraulic researchers and engineers. Currently, researchers claim that their models for the division lines are valid and yield good agreement with the experimental data from a channel flow that has a flat bed. It is not clear whether their models are still effective to model the division lines when the channel bed is curved. The aim of this paper is to examine the existence of division lines by analysing the distribution of mean velocity in a smooth culvert. The experiments reported here document a sufficient fact that it possible to observe the division lines from the velocity distribution. The method used to test the existence of the division line is to determine the normal distance from a boundary L n , based on the local boundary shear stress. The model from Yang and Lim (YLM) is selected for considerations in this comparison because other models were unable to produce the theoretical division lines in these cases. The division lines obtained from YLM are also plotted for various experimental flows to demonstrate the relationship between the experimental and theoretical division lines. This experimental analytical method developed for division lines may be extended to any arbitrary channels in other channel flows based on the results of the distribution of velocity.

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“…Shear stress is one of the important problems in sediment transport processes. In many cases, boundary shear stress on the channel wall is predicted in the form of an average value shear stress on the channel wall and bed [1][2][3]. For many years, a large number of experimental investigations have been carried out in open channels.…”

Section: Introductionmentioning

confidence: 99%

Comparison of five different models in predicting the shear stress distribution in straight compound channels

Khozani¹,

Bonakdari

2016

Scientia Iranica

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. SKM performed adequately in predicting the pattern of shear stress distribution on the main channel bed, but on a oodplain bed; it predicted a constant value over the entire wetted perimeter. The SKM method outperformed YLM and KPM with 2 to 20% MAPE. The ZAM and BAM methods produced the best results for shear stress distribution in compound channels with average MAPE of 2.67 and 5.66% MAPE , respectively. Although ZAM showed more accurate results than BAM, however, BAM required solving much fewer equations than ZAM and presented more accurate results than other geometric methods. Among all models, BAM is proposed as a simple and accurate model for predicting the shear stress distribution in compound channels.

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Shear Stress in Smooth Rectangular Open-Channel Flows

Cited by 149 publications

References 23 publications

Flow Hydrodynamics across Open Channel Flows with Riparian Zones: Implications for Riverbank Stability

Flow Hydrodynamics across Open Channel Flows with Riparian Zones: Implications for Riverbank Stability

Experimental Study of Flow Division in a Smooth Circular Culvert

Comparison of five different models in predicting the shear stress distribution in straight compound channels

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