Journal of Water and Sustainable Development

Hydrodynamic Analysis of Flow and Discharge Coefficient in Weirs with Porous Media under Free Overtopping Conditions

Document Type : Applied Article

Authors

Seyyed Alireza Esmaili
Majid Heydari
Saeed Gohari

Department of Water Science and Engineering, Faculty of Agriculture Bu-Ali Sina University, Hamedan, Iran

https://doi.org/10.22067/jwsd.v12i4.2508-1449
Abstract
In this experimental study, the discharge coefficient of flow over rectangular broad-crested weirs was examined under two conditions: solid and porous (gabion). For the porous weir, eight tests were conducted with effective lengths of 30 cm and 60 cm, using three gradations with mean particle diameters of 11 mm, 19 mm, and 28 mm. Initially, under free-flow conditions downstream of the weir, discharge coefficients for solid and gabion weirs were calculated and compared. Additionally, variations in velocity profiles and Reynolds shear stress distributions within the hydraulic domain of the weir were evaluated. The analysis of the water surface profile demonstrated that increasing gabion particle size reduced resistance to flow, thereby requiring a greater discharge to achieve fully overtopping conditions. Conversely, at constant discharge, increasing the weir length enhanced hydraulic resistance, leading to a higher upstream head. Examination of discharge coefficients revealed an increasing trend with longer weir lengths at equal discharges. On average, coefficients for porosities of 38%, 42%, and 45% were 0.74, 0.82, and 0.89 for the 30 cm weir, and 0.95, 1.00, and 1.20 for the 60 cm weir, respectively, whereas the solid weir yielded a coefficient of about 0.38. Furthermore, by applying a multivariable correlation equation and employing a gene expression programming (GEP) model based on dimensional analysis, an efficient predictive relationship for discharge over gabion weirs was developed, achieving a coefficient of determination of 98%.

Keywords

Porous Weir
Velocity Profiles
Reynolds Shear Stress
Water Surface Profile
GEP
Subjects
اسماعیلی، سیدعلیرضا، و گوهری، سعید، و حیدری، مجید. (1401). بررسی عوامل موثر در انتقال رسوب در جریان غیرماندگار. مهندسی عمران شریف، 38.2(1.1). 145-155. https://doi.org/10.24200/j30.2021.58434.2978.
هروی، زهرا، و اژدری مقدم، مهدی، و اسماعیلی، کاظم، و گیوه چی، محمد، و بحرپیما، عبدالحمید. (1403). ارزیابی آزمایشگاهی عملکرد طرح جدید مدل‌های محافظ بستر(F-jacks)  دراطراف پایه پل بر اصلاح الگوی جریان. نشریه هیدرولیک، 19(1). 67-87. https://doi.org/10.30482/jhyd.2023.395247.1643.
Azamathulla, H. M., Ghani, A. A., Zakaria, N. A., & Guven, A. (2010). Genetic programming to predict bridge pier scour. Journal of Hydraulic Engineering, 136(3), 165–169. https://doi.org/10.1061/(ASCE)HY.1943-7900.0000133.
Biabani, R., Salmasi, F., Nouri, M., & Abraham, J. (2022). Flow over embankment gabion weirs in free flow conditions. Journal of Hydro-Environment Research, 44, 65–76. https://doi.org/10.1016/j.jher.2022.03.003.
Chanson, H. (2006). Discussion of “Discharge through a permeable rubble mound weir” by Kohji Michioku, Shiro Maeno, Takaaki Furusawa, and Masanori Haneda. Journal of Hydraulic Engineering, 132(4), 432–433. https://doi.org/10.1061/(ASCE)0733-9429(2006)132:4(432).
Dhahir, F. M., & Mohammed-Hasan, A. M. (2017). Using of hydraulic jump characteristics as criterion for energy dissipation in rectangular gabion weir. International Journal of Advanced Research, 5(7), 268–276. https://doi.org/10.21474/IJAR01/4953.
Ergun, S. (1952). Fluid flow through packed columns. Chemical Engineering Progress, 48(2), 89–94.
Fathi-Moghaddam, M., Sadrabadi, M. T., & Rahmanshahi, M. (2018). Numerical simulation of the hydraulic performance of triangular and trapezoidal gabion weirs in free flow condition. Flow Measurement and Instrumentation, 62, 93–104. https://doi.org/10.1016/j.flowmeasinst.2018.05.005.
Heravi, Z., Moghaddam, M. A., Esmaili, K., Givehchi, M., & Bahrpeyma, A. (2024). Impact of installing new scour prevention countermeasure (F-jacks) around bridge pier on flow pattern and scour control. Ocean Engineering, 313, 119326. https://doi.org/10.1016/j.oceaneng.2022.112838.
Kim, S., Singh, V. P., & Seo, Y. (2014). Evaluation of pan evaporation modeling with two different neural networks and weather station data. Theoretical and Applied Climatology, 117(1), 1–13. https://doi.org/10.1007/s00704-013-0985-y.
Khatibi, R., Salmasi, F., Ghorbani, M. A., & Asadi, H. (2014). Modelling energy dissipation over stepped-gabion weirs by artificial intelligence. Water Resources Management, 28(7), 1807–1821. https://doi.org/10.1007/s11269-014-0595-z.
Leu, J. M., Chan, H. C., & Chu, M. S. (2008). Comparison of turbulent flow over solid and porous structures mounted on the bottom of a rectangular channel. Flow Measurement and Instrumentation, 19(6), 331–337. https://doi.org/10.1016/j.flowmeasinst.2008.03.004.
Michioku, K.,Maeno, S.,Furusawa, T., & Haneda, M. (2005). Discharge through a permeable rubble mound weir. Journal of Hydraulic Engineering, 131(1), 1–10. https://doi.org/10.1061/(ASCE)0733-9429(2005)131:1(1).
Mohamed, H. I. (2010). Flow over gabion weirs. Journal of Irrigation and Drainage Engineering, 136(8), 573–577. https://doi.org/10.1061/(ASCE)IR.1943-4774.0000217.
Rahmanshahi, M., & Shafai Bejestan, M. (2020). Gene-expression programming approach for development of a mathematical model of energy dissipation on block ramps. Journal of Irrigation and Drainage Engineering, 146(2), 04019033. https://doi.org/10.1061/(ASCE)IR.1943-4774.0001426.
Roushangar, K., Akhgar, S., Salmasi, F., & Shiri, J. (2014). Modeling energy dissipation over stepped spillways using machine learning approaches. Journal of Hydrology, 508, 254–265. https://doi.org/10.1016/j.jhydrol.2013.10.053.
Safarzadeh, A., & Mohajeri, S. H. (2018). Hydrodynamics of rectangular broad-crested porous weirs. Journal of Irrigation and Drainage Engineering, 144(10), 04018028. https://doi.org/10.1061/(ASCE)IR.1943-4774.0001347.
Sahu, C., Eldho, T. I., & Mazumder, B. S. (2023). Experimental study of flow hydrodynamics around circular cylinder arrangements using particle image velocimetry. Journal of Fluids Engineering, 145(1), 011302. https://doi.org/10.1115/1.4056024.
Salmasi, F., & Abraham, J. (2020). Discussion of “Hydrodynamics of rectangular broad-crested porous weirs” by Akbar Safarzadeh and Seyed Hossein Mohajeri. Journal of Irrigation and Drainage Engineering, 146(4), 07020003. https://doi.org/10.1061/(ASCE)IR.1943-4774.0001450.
Salmasi, F., Sabahi, N., & Abraham, J. (2021a). Discharge coefficients for rectangular broad-crested gabion weirs: Experimental study. Journal of Irrigation and Drainage Engineering, 147(3), 04021001. https://doi.org/10.1061/(ASCE)IR.1943-4774.0001487.
Salmasi, F., Sattari, M. T., & Nurcheshmeh, M. (2021b). Genetic programming approach for estimating energy dissipation of flow over cascade spillways. Iranian Journal of Science and Technology, Transactions of Civil Engineering, 45(1), 443–455. https://doi.org/10.1007/s40996-020-00541-3.
Sargison, J. E., & Percy, A. (2009). Hydraulics of broad-crested weirs with varying side slopes. Journal of Irrigation and Drainage Engineering, 135(1), 115–118.  https://doi.org/10.1061/(ASCE)0733-9437(2009)135:1(115).
Shariq, A., Hussain, A., & Ahmad, Z. (2020). Discharge equation for the gabion weir under through flow condition. Flow Measurement and Instrumentation, 74, 101769. https://doi.org/10.1016/j.flowmeasinst.2020.101769.
Shariq, A., Hussain, A., & Ahmad, Z. (2022). Flow over gabion weir under free and submerged flow conditions. Flow Measurement and Instrumentation, 86, 102199. https://doi.org/10.1016/j.flowmeasinst.2022.102199.
Yue, Z., Zhou, W., & Li, T. (2021). Impact of the Indian Ocean dipole on evolution of the subsequent ENSO: Relative roles of dynamic and thermodynamic processes. Journal of Climate, 34(9), 3591–3607. https://doi.org/10.1175/JCLI-D-20-0663.1.
Zahiri, A., & Najafzadeh, M. (2018). Optimized expressions to evaluate the flow discharge in main channels and floodplains using evolutionary computing and model classification. International Journal of River Basin Management, 16(1), 123–132. https://doi.org/10.1080/15715124.2017.1372442.
Send comment about this article
Enter Name.
Enter a valid email address.
Enter a vaid affiliation.
Enter comments (At leaset 10 words)
CAPTCHA Image
Enter Security Code Correctly.
Journal of Water and Sustainable Development
Volume 12, Issue 4 - Serial Number 38
Innovation and Technology in Water Management
Winter 2026
Pages 88-102

  • Receive Date 11 August 2025
  • Revise Date 05 September 2025
  • Accept Date 06 September 2025

Home

Guide for Authors

Submit Manuscript

Reviewers

Contact Us