Surface Roughness Effects on Discharge Coefficient of Broad Crested Weir

Jalil, Shaker A.; Ibrahim, Safa S.; Jafer, Rondk A.

doi:10.19026/rjaset.7.918

Cited by 10 publications

(6 citation statements)

References 11 publications

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“…Investigation on the effects of surface roughness sizes on the discharge coefficient for broad-crested weirs was carried out by [12]. Results showed that the logical negative effect of roughness increased with discharge for different lengths of the weir.…”

Section: Broad-crested Weirsmentioning

confidence: 99%

Review of Methods of Measuring Streamflow Using Hydraulic Structures

Adeogun¹,

Mohammed²

2020

Hydraulic Structures - Theory and Applications

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The measurement of streamflow is very critical to hydraulic engineers and hydrologists as it provides vital information for environmental monitoring issues connected to water resources. The objective of this study is to examine various means of measuring streamflow specifically application of hydraulic structures installed across the direction of flow. Weirs are restricted to small rivers where the provision for sufficient head and constriction in the river is acceptable. Sharpcrested weir is easy to construct, and it is commonly used as a flow measuring device in an open channel. Flumes are self-cleaning due to the fact that the flow velocity through a flume is usually high. Traditionally, flume is used in measuring flow in agricultural systems, and it requires low maintenance cost. It has capacity to measure more flow rates than weir. Accurate streamflow measurement using flume is within AE2-5% while that of weir is AE2%. Generally, flumes are employed to determine discharge where weirs are not useful.

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Section: Broad-crested Weirsmentioning

confidence: 99%

Review of Methods of Measuring Streamflow Using Hydraulic Structures

Adeogun¹,

Mohammed²

2020

Hydraulic Structures - Theory and Applications

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“…Weirs and gates are the most commonly used and important structures for measuring water flow, regulating flow in irrigation channels, and redirecting it from the main channel to secondary channels [1]. Weirs are structures that regulate water surface and flow control in water conveyance channels and hydraulic structures.…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study of a Combined Oblique Cylindrical Weir and Gate Structure

Ibrahim

Jafer

Ali

2023

Eng. Technol. Appl. Sci. Res.

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In the present study, the effects of different oblique angles and diameters on the cylindrical weir and below a gate as a combined device have been studied experimentally. For this purpose, sixteen models of combined cylindrical weir-gate structures have been tested in a laboratory flume. These models had four different oblique angles α (300, 450, 600, and 900). For each angle, the diameter of cylindrical weir-gate changed four times (4, 7.3, 9, and 11cm). The results of all models indicate that the theoretical discharge (Qth) is inversely proportional to the ratio of diameter to height (D/h) and length to height (L/h). As the diameter increases and oblique angles decrease, the actual discharge (Qact) increases. A general expression was established linking Qth/g1/2h5/2 and the discharge coefficient Cd with D/h, L/h, and alfa. The discharge coefficient ranged from 0.55 to 0.99 for various oblique angles and decreased as the angle increased. A strong correlation was observed between the estimated and the calculated values.

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“…The output of this study clarified flow patterns and governing relationships in the hydraulics of rectangular broad weirs. Jalil et al (2014) experimentally derived an empirical formula for the prediction of broad-crested weir discharge coefficients. The results showed that the performance of the broad crested weir is inversely proportional to the ratio of roughness to the weir height and the increase of the total head to the length.…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study of Flow over Rectangular Broad Crested Weir

Hamed

2022

ERJ. Engineering Research Journal

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The main objective of this study was to investigate the flow behavior of the broad crested weir (BCW) and establish a new formula describing the discharge coefficient. In the present work, an experimental study has been carried out on twenty-five BCW physical models with various geometrical configurations and surface roughness conditions too. Accordingly, the analysis highlights that discharge coefficient (Cd) values are directly proportional to the total head (H) acting on the broad crested weir for a fixed value of weir length (Lw) and increase with the decrease of weir surface roughness. The results showed (H/Lw) is the most studied effective BCW dimensionless ratio that significantly influences the discharge coefficient. An increasing H/Lw from 0.15 to 0.35 leads to noted discharge coefficient values increasing up to 28.39%. As consequence, a new formula with a more compact and short form of expression has been developed for the BCW discharge coefficient prediction. Moreover, a reasonable agreement was noticed between the present study results and the previous research-developed models with errors of less than 10%. Considering the proposed discharge coefficient formula, the optimum hydraulic design of the new BCW model can be successfully facilitated by the extrapolation of characteristics of the idealized scale. .

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Surface Roughness Effects on Discharge Coefficient of Broad Crested Weir

Cited by 10 publications

References 11 publications

Review of Methods of Measuring Streamflow Using Hydraulic Structures

Review of Methods of Measuring Streamflow Using Hydraulic Structures

An Experimental Study of a Combined Oblique Cylindrical Weir and Gate Structure

An Experimental Study of Flow over Rectangular Broad Crested Weir

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