![Sample our Environment & Sustainability journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5935/TOC-Subject-Sample-2021-Environment-Sustainability.jpg"})
ABSTRACT
Side weirs or lateral weirs are widely employed to divert flows from rivers, channels, sewers and reservoirs or to divide flows between components of water treatment systems. The side weir is a fixed structure installed at one side of a channel for water level control in water treatment plants and irrigation and drainage systems. Hydraulic characteristics of a compound sharp-crested triangular–rectangular side weir under subcritical flow were studied in this paper. The concept of the elementary discharge coefficient that is related to the head to weir height ratio was used to determine the flow through the side weir. The advantage of this method is to calculate the channel water surface profile along the weir. Generalized equations for an elementary discharge coefficient for compound triangular–rectangular side weirs were proposed. Experimental results show the accuracy of the proposed equations.
Acknowledgements
The authors are grateful to the Islamic Azad University, Shahrood Branch and the Golestan Regional Water Authority for their support.
Disclosure statement
No potential conflict of interest was reported by the authors.
List of symbols
|
| = | cross-sectional area of flow (m2) |
| B | = | width of main channel (m) |
|
| = | width of the two side sections (m) |
|
| = | width of triangular part (m) |
|
| = | elementary coefficient of discharge |
|
| = | average percentage error (%) |
|
| = | approach Froude number |
|
| = | Froude number at distance |
|
| = | acceleration due to gravity (m s−2) |
| i | = | number of elements |
|
| = | unknown positive constants |
|
| = | distance between sections 1 and 2 along the weir (m) |
|
| = | discharge in the channel (m3 s−1) |
|
| = | discharge at the upstream of side weir (m3 s−1) |
|
| = | discharge at the downstream of side weir (m3 s-1) |
|
| = | computed weir discharge (m3 s−1) |
|
| = | observed weir discharge (m3 s−1) |
|
| = | discharge over side weir (m3 s−1) |
| n | = | manning's roughness coefficient |
|
| = | slope of the energy grade line |
|
| = | slope of channel bed |
|
| = | top width of channel section (m) |
|
| = | mean velocity in main channel (m s−1) |
|
| = | mean velocity of flow at distance |
|
| = | weir height (m) |
|
| = | height of the two side sections (m) |
|
| = | height of triangular part (m) |
|
| = | height of weir crest at distance |
|
| = | ratio of weighted crest height of the weir (m) |
|
| = | distance along side weir (m) |
|
| = | depth of flow (m) |
|
| = | depth of flow at distance |
|
| = | kinetic energy correction factor |
|
| = | relative overflow depth |
|
| = | apex angle (°) Suffixes 1 and 2 denote the upstream and downstream conditions, respectively. |