Influences of sedimentation on overflow properties of sharp-crested weir

A sharp-crested weir is the simplest type of weir and is mainly used for discharge measurement in open channels. The surface profile of an ogee weir also is designed based on the lower nappe profile of the free jet passing over a sharp-crested weir. In the current study, influences of sedimentation...

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Main Authors: Mohammad Mehdi Farzanmehr, Jahanshir Mohammadzadeh-Habili
Format: Article
Language:English
Published: KeAi Communications Co., Ltd. 2025-02-01
Series:International Journal of Sediment Research
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S1001627924001240
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author Mohammad Mehdi Farzanmehr
Jahanshir Mohammadzadeh-Habili
author_facet Mohammad Mehdi Farzanmehr
Jahanshir Mohammadzadeh-Habili
author_sort Mohammad Mehdi Farzanmehr
collection DOAJ
description A sharp-crested weir is the simplest type of weir and is mainly used for discharge measurement in open channels. The surface profile of an ogee weir also is designed based on the lower nappe profile of the free jet passing over a sharp-crested weir. In the current study, influences of sedimentation on the discharge coefficient and lower nappe profile of a sharp-crested weir were experimentally investigated. The results indicated that for a specific discharge value, an increase in upstream sedimentation depth results in the reduction in the water level of the approach flow to the sharp-crested weir, and, consequently, a reduction in the weir water head. As the discharge coefficient is inversely influenced by the weir water head, increases in the sedimentation depth resulted in raising the discharge coefficient of the sharp-crested weir up to 42%. Furthermore, the results indicated that with increases in upstream sedimentation depth, the lower nappe profile of the free jet passing over the sharp-crested weir tends toward that of a vertical drop. Under upstream sedimentation, the discharge coefficient of the sharp-crested weir is mainly influenced by the weir's effective height (difference between weir height and sedimentation depth) and it is minimally influenced by sediment grain sizes. Using the experimental results supported by dimensional analysis, the discharge coefficient of the sharp-crested weir was accurately derived as an increasing function of the ratio of weir water head to weir effective height.
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publisher KeAi Communications Co., Ltd.
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spelling doaj-art-25548067c22445dbaff9cb7af607b7982025-01-12T05:24:19ZengKeAi Communications Co., Ltd.International Journal of Sediment Research1001-62792025-02-01401172181Influences of sedimentation on overflow properties of sharp-crested weirMohammad Mehdi Farzanmehr0Jahanshir Mohammadzadeh-Habili1Department of Water Engineering, School of Agriculture, Shiraz University, Shiraz, 7144113131, Islamic Republic of IranCorresponding author.; Department of Water Engineering, School of Agriculture, Shiraz University, Shiraz, 7144113131, Islamic Republic of IranA sharp-crested weir is the simplest type of weir and is mainly used for discharge measurement in open channels. The surface profile of an ogee weir also is designed based on the lower nappe profile of the free jet passing over a sharp-crested weir. In the current study, influences of sedimentation on the discharge coefficient and lower nappe profile of a sharp-crested weir were experimentally investigated. The results indicated that for a specific discharge value, an increase in upstream sedimentation depth results in the reduction in the water level of the approach flow to the sharp-crested weir, and, consequently, a reduction in the weir water head. As the discharge coefficient is inversely influenced by the weir water head, increases in the sedimentation depth resulted in raising the discharge coefficient of the sharp-crested weir up to 42%. Furthermore, the results indicated that with increases in upstream sedimentation depth, the lower nappe profile of the free jet passing over the sharp-crested weir tends toward that of a vertical drop. Under upstream sedimentation, the discharge coefficient of the sharp-crested weir is mainly influenced by the weir's effective height (difference between weir height and sedimentation depth) and it is minimally influenced by sediment grain sizes. Using the experimental results supported by dimensional analysis, the discharge coefficient of the sharp-crested weir was accurately derived as an increasing function of the ratio of weir water head to weir effective height.http://www.sciencedirect.com/science/article/pii/S1001627924001240Sharp-crested weirSedimentationDischarge coefficientEffective heightLower nappe
spellingShingle Mohammad Mehdi Farzanmehr
Jahanshir Mohammadzadeh-Habili
Influences of sedimentation on overflow properties of sharp-crested weir
International Journal of Sediment Research
Sharp-crested weir
Sedimentation
Discharge coefficient
Effective height
Lower nappe
title Influences of sedimentation on overflow properties of sharp-crested weir
title_full Influences of sedimentation on overflow properties of sharp-crested weir
title_fullStr Influences of sedimentation on overflow properties of sharp-crested weir
title_full_unstemmed Influences of sedimentation on overflow properties of sharp-crested weir
title_short Influences of sedimentation on overflow properties of sharp-crested weir
title_sort influences of sedimentation on overflow properties of sharp crested weir
topic Sharp-crested weir
Sedimentation
Discharge coefficient
Effective height
Lower nappe
url http://www.sciencedirect.com/science/article/pii/S1001627924001240
work_keys_str_mv AT mohammadmehdifarzanmehr influencesofsedimentationonoverflowpropertiesofsharpcrestedweir
AT jahanshirmohammadzadehhabili influencesofsedimentationonoverflowpropertiesofsharpcrestedweir