Numerical Modeling of the Flow Passing through a Rectangular Linear Weir with Flat Crest Shape

Year 2024, Volume: 19 Issue: 1, 46 - 56

Ali Yıldız

Abstract

The most common hydraulic structures used for discharge measurements in open channels are linear weirs due to their accuracy, simplicity, design, and ease of construction. Linear weirs are also used to increase flow depth, control floods, and regulate flow. Before the actual on-site manufacturing of weirs, their hydraulic properties must be determined with experimental and numerical studies. In this study, experiments were carried out on a rectangular linear weir with dimensions 60 x 30, 30 cm height, 1 cm thickness and a flat crest shape. 2D numerical models of the flow passing over the weir were created using the Fluent program. The data obtained from the experimental and numerical model were evaluated in terms of flow depth, total head, discharge coefficient (Cd) and water surface profile. According to the results, although there are differences between the models in the discharge-total comparison due to the working principle of the 2-dimensional numerical model, the models gave 90%-95% consistent results in the discharge coefficient and dimensionless total head comparison. In addition, the experimental and numerical models were compared visually, and it was seen that the numerical models of the experiments were created with a high degree of accuracy.

Keywords

Experimental Modelling, Linear Weirs, Numerical Modelling, Sharp-Crested Weirs

References

• Arvanaghi H, Nasehi Oskuei N, (2013) Sharp-Crested Weir Discharge Coefficient. Scienceline Journals. J. Civil Engin. & Urban., 3(3), 87–91. https://www.ojceu.ir/main/attachments/article/24/JCEU-C3-15.pdf
• Aydin I, Altan-Sakarya AB, Sisman C, (2011) Discharge formula for rectangular sharp-crested weirs. Flow Measur. & Instr., 22(2), 144–151. https://doi.org/10.1016/J.flowmeasinst.2011.01.003
• Bagheri S, Heidarpour M, (2010) Flow over rectangular sharp-crested weirs. Irrig. Sci., 28(2), 173–179. https://doi.org/10.1007/S00271-009-0172-1/figures/9
• Boileau P, (1854) Traite de la mesure des eaux courantes. Prag. https://www.eyrolles.com/Loisirs/Livre/traite-de-la-mesure-des-eaux-courantes-9782329944135/
• Bos MG, (1978) Discharge measurement structures. ILRI Publication 20, WL Publicatie 161. https://repository.tudelft.nl/islandora/object/uuid%3Abed11d85-f4af-46d1-ba58-7d71f8c8f9c2
• Escande L, Sabathé G, (1937) Inclined weir relative to the channel axis. Comptes Rendus de l’Académie Des Sciences, 204, 1547–1549. https://comptes-rendus.academie-sciences.fr/
• Falvey H T, (2002) Hydraulic Design of Labyrinth Weirs. Hydraulic Design of Labyrinth Weirs, 1–160. https://doi.org/10.1061/9780784406311
• Ansys® Fluent, (2023), Chapter 1: Basic Fluid Flow, Help System, ANSYS, Inc., n.d.
• Han TY, Chow, W L, (1981) The Study of Sluice Gate and Sharp-Crested Weir Through Hodograph Transformations. Journal of Applied Mechanics, 48(2), 229–238. https://doi.org/10.1115/1.3157602
• Henderson FM, (Francis M. (1966) Open channel flow. 522. Retrieved from https://books.google.com/books/about/Open_Channel_Flow.html?hl=tr&id=4whSAAAAMAAJ
• Horton RE, (1907) Weir experiments, coefficients, and formulas. Washington: government printing office. https://pubs.usgs.gov/wsp/0150/report.pdf
• Istomina VS, (1937) Oblique weirs with sharp and broad crests. L’Energia Elettrica, 14(2) 178–181.
• Khan AA, Steffler PM, (1996) Modeling Overfalls Using Vertically Averaged and Moment Equations. Journal of Hydraulic Engineering, 122(7), 397–402. https://doi.org/10.1061/(ASCE)0733-9429(1996)122:7(397)
• Kindsvater CE, Carter RW, (1957) Discharge Characteristics of Rectangular Thin-Plate Weirs. Journal of the Hydraulics Division, 83(6), 1453–1. https://doi.org/10.1061/JYCEAJ.0000142
• Kumar S, Ahmad Z, Mansoor T, (2011) A new approach to improve the discharging capacity of sharp-crested triangular plan form weirs. Flow Measurement and Instrumentation, 22(3), 175–180. https://doi.org/10.1016/J.flowmeasinst.2011.01.006
• Mahtabi G, Arvanaghi H, (2018) Experimental and numerical analysis of flow over a rectangular full width sharp-crested weir. Water Science and Engineering, 11(1), 75-80. https://doi.org/10.1016/j.wse.2018.03.004
• Qu J, Ramamurthy AS, Tadayon R, Chen Z, (2009), Numerical simulation of sharp-crested weir flows. Can. J. Civ. Eng., 36(9), 1530-1534. https://doi.org/10.1139/L09-067
• Rajaratnam, N., & Muralidhar, D. (1971). Pressure and velocity distribution for sharp-crested weirs. Journal of Hydraulic Research, 9(2), 241–248. https://www.informahealthcare.com/toc/tjhr20/9/2?nav=tocList
• Rouse H, Kandaswamy P, (1957) Characteristics of flow over terminal weirs and sills. J. of Hydraulics., 83, 1-13. https://www.scirp.org/reference/referencespapers?referenceid=1834236
• Rouse H, Reid L, (1935) Model research on spillway crests. Journal of Hydraulic Engineering, 132(12), 1248-1258. https://doi.org/10.1061/(ASCE)0733-9429(2006)132:12(1248)
• Tullis JP, Amanian N, Waldron D, (1995) Design of Labyrinth Spillways. Journal of Hydraulic Engineering, 121(3), 247-255. https://doi.org/10.1061/(asce)0733-9429(1995)121:3(247)