A new method of predicting the flow in a 90° branch channel

Krishnappa, G.; Seetharamiah, K.

doi:10.1051/lhb/1963055

Cited by 15 publications

(6 citation statements)

References 1 publication

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“…It was observed that there is a strong linear relationship between the discharge ratio (Q r ) and the Froude number in all cases. Moreover, there is a reverse relationship between Q r and F u , which is consistent with the results of Krishnappa and Seetharamiah (1963), Hager (1987), and Bejestan et al (2013), and between Q r and F b . In addition, based on the maximum branch channel discharge, the best angle for the diversion channel is 45° from among 45, 60, 75, and 90°.…”

Section: Relationship Between Discharge Ratio and Froude Numbersupporting

confidence: 90%

An experimental study of branching flow in open channels

Sayed

2019

Limnological Review

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Branching channel flow describes any side water withdrawals from rivers or main channels. Branching channels have widespread application in many practical projects, such as irrigation and drainage network systems, water and waste-water treatment plants, and many water resources projects. Therefore, in this research, a comprehensive analysis of laboratory data has been carried out to discover the best angle of branching. The study also aims to introduce simple, practical equations to help engineers of water resources to fix the percentage of discharge diverted to the branch channel. The study was carried out in the Irrigation and hydraulics laboratory of the civil department, Faculty of Engineering, Assiut University. The laboratory channel consisted of two parts, the main channel, and a branch channel. The main channel was 8.0 m in length, 20 cm wide, and 20 cm in depth. The division corner to the branch channel was sharp edged and located 5.0 m downstream of the main channel inlet. The branch channel was 3.0 m long, 20 cm in depth and its width was changed three times (10, 15, and 20 cm) respectively. A total of 84 runs were carried out. Investigations of the flow into the branching channel show that the branching discharge depends on many interlinked parameters. It increases with a decrease of the main channel flow velocity and the Froude number upstream of the branch channel junction. It also increases with an increase in the Yb / Yu ratio. In subcritical flow, water depth in the branch channel is always lower than the main channel water depth. The flow diversion to the branch channel leads to a decrease in water depth downstream of the main channel. In addition, the study showed that the highest discharge rate was obtained when the angle of branching was equal to 45° and then an angle of 60o. While the lowest discharge rate was obtained at an angle of 90°. Furthermore, at Br = 1.0, using a branching angle equal to 45° the discharge ratio (Qr) increases from about 4.42 to 19.01%, more than that obtained with using the branching angle equal 90°, while the discharge ratio (Qr) increases from about 0.52 to 49.18% and 1.51 to 24.79%, at Br = 0.75, and Br = 0.5 respectively.

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Section: Relationship Between Discharge Ratio and Froude Numbersupporting

confidence: 90%

An experimental study of branching flow in open channels

Sayed

2019

Limnological Review

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“…Krishnappa and Seetharamiah (1963) and Ramamurthy and Satish (1988) used the inlet Froude number, which is not suitable (Fig. 5a), however.…”

Section: Empirical Correlation Of Discharge Distributionmentioning

confidence: 99%

“…This state is ensured if the Froude number in the lateral branch is larger than the threshold value of 0.34 (0.35 by Satish 1988 and1/3 by Hager 2010). The presence of a critical flow section was used to characterize the discharge division analytically (Ramamurthy and Satish 1988) or empirically (Krishnappa and Seetharamiah 1963, Lakshmana Rao and Sridharan 1967, Rivière et al 2007). This work focuses on different cases of transcritical flow division, namely junction inlet flow under the critical regime.…”

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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“…Moreover, both empirical formulae (e.g. [9]) and simplified models based on macroscopic control volumes [10] have been derived for channel bifurcations, but in the case of a dike break, the flow leaving the main channel is not confined by lateral walls but can spread in all directions. There is therefore a need for a simplified model designed for the specific case of dike-break induced flows, all the more so because general empirical formulae (e.g.…”

mentioning

confidence: 99%

Dike-break induced flows: a simplified model

et al. 2012

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A simplified model for the prediction of the steady-state outflow through a breach in an inland dike is presented. It consists in the application of the mass and momentum conservation principles to a macroscopic control volume. A proper definition of the shape of the control volume enables to take the main characteristics of the flow into account and thus to compensate for the extreme simplification of the spatial representation of the model. At the breach, a relation derived from the shallow-water equations is used to determine the direction of the flow. Developments have been guided by numerical simulations and results have been compared to experimental data. Both the accuracy and the domain of validity of the simplified model are found satisfactory.

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A new method of predicting the flow in a 90° branch channel

Abstract: The discharge distribution decreases as the Froude number increases.

Cited by 15 publications

References 1 publication

An experimental study of branching flow in open channels

An experimental study of branching flow in open channels

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

Dike-break induced flows: a simplified model

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