Hydraulics CHARACTERISTICS OF FLOW OVER CONTRACTED CLEAR OVERFALL WEIRS WITH BOTTOM-PIPES | ||||
| JES. Journal of Engineering Sciences | ||||
| Article 4, Volume 42, No 2, March and April 2014, Page 325-340 PDF (285.28 K) | ||||
| Document Type: Research Paper | ||||
| DOI: 10.21608/jesaun.2014.114736 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
| G. A. Abd El-Raheem1; Ahmed M. El-Belasy2; Salah M. Shehata3 | ||||
| 1Professor of Hydraulics and Water Resources, Department of Civil Engineering, Assiut University, Assiut 71516, Egypt | ||||
| 2Associate Prof., Hydraulics Research Institute, National Water Research Center, Egypt. | ||||
| 3Doctorate Student, Civil Eng. Dept., Assiut Univ., Assiut, Egypt. | ||||
| Abstract | ||||
| Fayoumi Standard Weirs have been modified by adding one, two or three pipes, to convey much water to downstream direction. Measurements of discharge with these structures are complicated due to existence of the openings. In this research, an experimental study is carried out to investigate the effect of installing pipes through a piped clear over fall weir and bottom-pipes. Twelve weir models with different heights are tested in horizontal laboratory flume of 17 m length, 0.3 m width, and 0.5 m depth. Weir height is changed two times. Contraction of weirs is changed two times. For each one, the diameter of opening is changed three times. The downstream depth is changed to cover all the concerned flow regimes of flow rate for a submerged pipe and a free weir. The downstream water depth begins with the upper tangent of the pipe and ends with the crest level of the weir. The contraction and the un-contraction of the weir are discussed. The effect of downstream water depth is taken into consideration. The results of flow over weir with opening are compared with those of weir without opening having the same dimensions. It is found that there is a large difference between them. Multiple regression equations based on energy principal and dimensional analysis theory are developed for computing discharge over clear over fall weir with bottom pipes. Also, values of discharge coefficients were estimated for combined flow over the weir and through the pipe. Then the total discharge can be computed by multiplying the discharge coefficient by the summation of theoretical weir discharge plus theoretical orifice discharge. Equations for computing the discharge of combination are awarded. | ||||
| Keywords | ||||
| Fayoumi weir; bottom pipes; free discharge; discharge coefficient; contracted and un-contracted piped-weirs | ||||
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