A geometrical method for computing the distribution of boundary shear stress across irregular straight open channels

Khodashenas, Saeed Reza; Paquier, André

doi:10.1080/00221686.1999.9628254

Cited by 79 publications

(34 citation statements)

References 10 publications

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“…This implies an additional sub-model to the 1D model. Based on the merged perpendicular method (noted MP method hereafter, see Khodashenas & Paquier, 1999), the bed shear stress is estimated across the section neglecting transverse bottom slope. Thus, the local hydraulic radius equals the vertical distance from the bottom to the first delimiter, which is either a bissector (geometrical division line between the flow influenced by the bank roughness and the flow influenced by the main channel roughness) or the water surface.…”

Section: Distribution Of Bed Shear Stress Throughout the Sectionmentioning

confidence: 99%

Assessment of Methods Used in 1D Models for Computing Bed-Load Transport in a Large River: The Danube River in Slovakia

et al. 2011

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Comprehensive measurements of bedload sediment transport through a section of the Danube River, located approximately 70km downstream from Bratislava, Slovakia, are used to assess the accuracy of bedload formulae implemented in 1D modelling. Depending on water discharge and water level, significant variations in the distribution of bedload across the section were observed. It appeared that, whatever the water discharge, the bed shear stress τ is always close to the estimated critical bed shear stress for the initiation of sediment transport τ cr . The discussion focusses on the methods used in 1D models for estimating bedload transport. Though usually done, the evaluation of bedload transport using the mean cross-sectional bed shear stress yields unsatisfactory results. It is necessary to use an additional model to distribute the bed shear stress across the section and calculate bedload locally. Bedload predictors also need to be accurate for τ close to τ cr . From that point of view, bedload formulae based on an exponential decrease of bedload transport close to τ cr appear to be more appropriate than models based on excess bed shear stress. A discussion on the bedload formula capability to reproduce grain sorting is also provided.

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Section: Distribution Of Bed Shear Stress Throughout the Sectionmentioning

confidence: 99%

Assessment of Methods Used in 1D Models for Computing Bed-Load Transport in a Large River: The Danube River in Slovakia

et al. 2011

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“…With the exception of the methods outlined by Lundgren and Jonnson (1964), Yang and Lim (1997), Zheng and Jin (1998) and Khodashenas and Paquier (1999), the majority of approaches require either a large amount of computer resources or reliance on certain contentious assumptions. The aim of this paper is to examine the possibility of using Shannon's (1948) entropy concept in order to predict the boundary shear stress in open channel flow.…”

Section: Introductionmentioning

confidence: 97%

An attempt at using the entropy approach to predict the transverse distribution of boundary shear stress in open channel flow

Sterling

Knight

2002

Stochastic Environmental Research and Risk Assessment (SERRA)

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This paper highlights the similarities between a number of studies which have applied the concept of Shannon's entropy to Hydraulic Engineering. The entropy concept is further developed in an attempt to predict the transverse distribution of boundary shear stress in circular open channels. The approach is also extended and applied to circular channels with a flat bed and trapezoidal channels, and the Lagrange multipliers, k, found by recourse to empirical equations. Doubts are expressed concerning the value of the entropy approach to such problems.

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“…This method fails when channel walls have a steep slope, because the intersection of normal occurs below the water surface. To solve this problem, Khodashenas and Paquier [11] extended the normal area method and predicted shear stress distribution in an irregular cross section of a channel. The shear stress distribution was calculated as follows:…”

Section: Khodashenas and Paquier's Methods (Kpm)mentioning

confidence: 99%

“…Studies have shown that it is di cult to determine the boundary shear stress distribution in an open channel [4][5][6][7][8][9]. To overcome this di culty, empirical, analytical, and simpli ed computational methods have been conducted by several researchers [10][11][12][13][14][15][16][17][18][19][20][21]. Still, even with sophisticated turbulence models, it is challenging to accurately calculate local shear stress values.…”

Section: Introductionmentioning

confidence: 99%

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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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A geometrical method for computing the distribution of boundary shear stress across irregular straight open channels

Cited by 79 publications

References 10 publications

Assessment of Methods Used in 1D Models for Computing Bed-Load Transport in a Large River: The Danube River in Slovakia

Assessment of Methods Used in 1D Models for Computing Bed-Load Transport in a Large River: The Danube River in Slovakia

An attempt at using the entropy approach to predict the transverse distribution of boundary shear stress in open channel flow

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

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