The calibration of sharp-crested weirs with a horizontal edge used for measuring flows in partially full pipes
DOI:
https://doi.org/10.24425/jwld.2023.148455Abstract
This paper presents the results of a laboratory study on the discharge capacity of sharp-crested weirs fitted with a horizontal edge in pipes during open-channel flow conditions and clean water used to measure the outflow. Such sharp-crested weirs are mounted in pipes and are used to control the inflow to separators. The stream profile does not correspond to the profile given by Bazin for sharp crested weirs in channels. A desired location of the water level measurement point for flow rate calculations was provided. Discharge curves were identified for three sharp-crested weirs of 0.0465, 0.0634 and 0.0771 m in height, installed in the pipe of 0.1534 m in diameter and inclinations of 0.5 and 1.0%. The discharge curves for weir flow with free nappe does not show a significant effect of the pipe slope on the weir discharge capacity. The non-dimensional formulas for the discharge capacity of the sharp-crested weir were found as general polynomial regressions. The results indicate that the calibrated sharp-crested weir with a horizontal edge placed in a pipe can be used to control the flow. Due to the scale effect, relationships obtained from the calibration cannot be generalised to other pipe diameters and weirs heights than those analysed.References
Addison, H. (1941) Hydraulic measurements: a manual for engineers. New York: John Wiley & Sons.
Bettez, J., Townsend, R.D. and Comeau, A. (2001) “Scale model testing and calibration of City of Ottawa sewer weirs,” Canadian Journal of Civil Engineering, 28(4), pp. 627–639. Available at: https://doi.org/10.1139/l01-024.
Chow, V.T. (1959). Open-channel hydraulics. McGraw-Hill.
Erickson, A.J., Weiss, P.T. and Gulliver, J.S. (2013) Optimizing stormwater treatment practices: A handbook of assessment and maintenance. New York, NY: Springer. Available at: https://doi.org/10.1007/978-1-4614-4624-8.
Hager, W.H. (1991) “Backwater curves in circular channels,” Journal of Irrigation and Drainage Engineering, 117(2), 25696, pp. 173–183.
Kindsvater, C.E. and Carter, R.W. (1959) “Discharge characteristics of rectangular thin-plate weirs,” Transactions of the American Society of Civil Engineers, 124(1), pp. 772–801.
Kotowski, A. (2011) Podstawy bezpiecznego wymiarowania odwodnień terenów [Basics of safe dimensioning of land drainage]. Warszawa: Seidel-Przywecki.
Kubrak, J. (1981) Badanie warunków przepływu nad przelewami o bezciśnieniowych profilach korony [Investigation of flow conditions over spillways with pressureless crested weirs]. PhD Thesis. Warszawa: Szkoła Główna Gospodarstwa Wiejskiego.
Kubrak, E. and Kubrak, J. 2022. “Practical aspects of the use of the sluice gate discharge equations to estimate the volumetric flow rate in the irrigation channels,” Journal of Water and Land Development, 55, pp. 129–137. Available at: https://doi.org/10.24425/jwld.2022.142315.
Oliveto, G. and Hager, W.H. (1997) “Discharge measurement in circular sewer,” Journal of Irrigation and Drainage Engineering, 123, pp. 138–140.
Troskolański, A.T. (ed.) (2014) Vocabulary of mechanics in five languages English/German/French/Polish/Russian. Vol. 2. Group. 15 Mechanics of fluids. Oxford: Pergamon Press, Warsaw: Wydawnictwa Naukowo-Techniczne.
Ranga Raju, K.G. and Asawa, G.L. (1977) “Viscosity and surface tension effects on weir flow,” Journal of the Hydraulics Division, 103(10), pp. 1227–1231. Available at: https://doi.org/10.1061/JYCEAJ.0004857.
Rao, N.S.L. (1975) “Theory of weirs,” Advances in Hydroscience, 10, pp. 309–406. Available at: https://doi.org/10.1016/B978-0-12-021810-3.50009-6.
Sokołowski, M.J. 2015. Badanie przepustowości niezatopionego przelewu o ostrej krawędzi w bezciśnieniowym przewodzie kołowym [Study of the capacity of a non-submerged sharp crested weir in a non-pressure circular pipe]. MSc Thesis. Warszawa: Szkoła Główna Gospodarstwa Wiejskiego.
Unser, K. and Holzke, H. (1975) “Abflusß an scharfkantigen Wehren ohne Seitenkontraktion bei anliegendem, unbelüftetem Überfall-strahl [Discharge of sharp crested overflow-weirs without side contraction with adjacent, non-areayed Nappe],” Wasser Und Boden, 12, pp. 314–317.
Vatankhah, A.R. and Khalili, S. (2017) “Sharp-crested weir located at the end of a circular channel,” Proceedings of the Institution of Civil Engineers – Water Management, 170(6), pp. 287–297. Available at: https://doi.org/10.1680/jwama.16.00032.
