A Semi-Theoretical Study on the Effect of Rough Beds on the Conjugate Depth Ratio in Hydraulic Jumps
Received: 28 February 2025 | Revised: 25 March 2025 | Accepted: 4 April 2025 | Online: 16 April 2025
Corresponding author: Khechiba Haroun
Abstract
This study examines the effects of bed roughness on hydraulic jump characteristics in rectangular composite channels. Experiments were conducted in a laboratory flume with two roughness zones: the main channel and the floodplain, using uniform plastic granules to simulate different roughness conditions. The results show that increased bed roughness significantly reduces the subsequent depth ratio. A semi-theoretical dimensionless approach was developed to analyze the hydraulic jump, incorporating key parameters, such as the incident Froude number, the resistance coefficient, the expansion ratio, the shape factor, and the conjugate depth ratio. This approach, based on Euler's theory applied between two sections of the hydraulic jump, allows the conjugate depth ratio to be predicted using the flow rate and the tested absolute roughness values. The experimental validation confirms the accuracy of this model in estimating the conjugate depth ratio under varying roughness conditions. The developed approach provides a practical tool for engineers to optimize hydraulic structures in channels with variable roughness and zero slope, improving flow regulation and reducing erosive forces.
Keywords:
hydraulic jump, bed roughness, conjugate depth ratio, rectangular compound channel, rough bedDownloads
References
W. H. Hager, Energy Dissipators and Hydraulic Jump,. Dordrecht, Netherlands: Springer Netherlands, 1992.
N. Rajaratnam, "Hydraulic Jumps," in Advances in Hydroscience, vol. 4, V. T. Chow, Ed. Elsevier, 1967, pp. 197–280.
F. G. Carollo, V. Ferro, and V. Pampalone, "Hydraulic Jumps on Rough Beds," Journal of Hydraulic Engineering, vol. 133, no. 9, pp. 989–999, Sep. 2007.
S. Dey and A. Sarkar, "Characteristics of Turbulent Flow in Submerged Jumps on Rough Beds," Journal of Engineering Mechanics, vol. 134, no. 1, pp. 49–59, Jan. 2008.
H. J. Leutheusser and E. W. Schiller, "Hydraulic jump in open channels—some properties," Journal of Hydraulic Research, vol. 13, no. 1, pp. 17–36, 1975.
H. Velioğlu, "Effect of rough bed on hydraulic jump characteristics," Water Science and Engineering, vol. 5, no. 1, pp. 95–106, 2012.
S. A. Ead and N. Rajaratnam, "Hydraulic Jumps on Corrugated Beds," Journal of Hydraulic Engineering, vol. 128, no. 7, pp. 656–663, Jul. 2002.
F. Bahmanpouri, C. Gualtieri, and H. Chanson, "Flow patterns and free-surface dynamics in hydraulic jump on pebbled rough bed," Proceedings of the Institution of Civil Engineers - Water Management, vol. 176, no. 1, pp. 32–49, Apr. 2021.
N. Afzal, A. Bushra, and A. Seena, "Analysis of Turbulent Hydraulic Jump over a Transitional Rough Bed of a Rectangular Channel: Universal Relations," Journal of Engineering Mechanics, vol. 137, no. 12, pp. 835–845, Dec. 2011.
U. Türker and M. Valyrakis, "Hydraulic jump on rough beds: conceptual modeling and experimental validation," Water Supply, vol. 21, no. 4, pp. 1423–1437, Nov. 2020.
N. Agrawal and E. Padhi, "Impacts of bed roughness and orientation on hydraulic jump: A review," Water Science and Engineering, vol. 18, no. 1, pp. 90–101, Mar. 2025.
L. A. M. Saleh and S. I. Khassaf, "A review study on the effect of artificial bed roughness on the performance of prismatic hydraulic jump stilling basins," AIP Conference Proceedings, vol. 3091, no. 1, May 2024, Art. no. 020010.
A. Benabdesselam, B. Achour, and L. Houichi, "Hydraulic Jumps in a Straight Rectangular Compound Channel: Theoretical Approach and Experimental Study," LARHYSS Journal, vol. 29, pp. 323–340, Jan. 2017.
T. Mohamed Ali, "Effect of roughened-bed stilling basins on the characteristics of hydraulic jumps," Journal of Hydraulic Research, vol. 29, no. 5, pp. 565–585, 1991.
R. Maleki and V. Fiorotto, "Experimental investigation of hydraulic jumps over roughened beds in rectangular channels," Journal of Hydraulic Engineering, vol. 147, no. 8, Aug. 2021.
H. Samadi-Boroujeni, M. Ghazali, B. Gorbani, and R. F. Nafchi, "Effect of triangular corrugated beds on the hydraulic jump characteristics," Canadian Journal of Civil Engineering, vol. 40, no. 9, pp. 841–847, Sep. 2013.
M. K. Beirami and M. R. Chamani, "Hydraulic jump in sloping channels: roller length and energy loss," Canadian Journal of Civil Engineering, vol. 37, no. 4, pp. 535–543, Apr. 2010.
M. Kumar and A. S. and Lodhi, "Hydraulic jump over sloping rough floors," ISH Journal of Hydraulic Engineering, vol. 22, no. 2, pp. 127–134, May 2016.
A. Kavousizadeh, S. Eslamian, and V. P. Singh, "Analysis of hydraulic jump on rough beds in urban drainage systems," Urban Water Journal, vol. 16, no. 2, pp. 121–131, 2019.
S. K. Gupta and V. K. Dwivedi, "Experimental investigation of hydraulic jump characteristics in sloping rough surfaces for sustainable development," Engineering Research Express, vol. 6, no. 2, Apr. 2024, Art. no. 025103.
N. M. Ngoc and T. N. Thang, "A Study of an Empirical Sequent Depths Equation of the Hydraulic Jump in a Horizontal Trapezoidal Channel," Engineering, Technology & Applied Science Research, vol. 13, no. 6, pp. 12307–12313, Dec. 2023.
D. Valero, N. Viti, and C. Gualtieri, "Numerical Simulation of Hydraulic Jumps. Part 1: Experimental Data for Modelling Performance Assessment," Water, vol. 11, no. 1, Jan. 2019, Art. no. 36.
A. Ghomri and F. Riguet, "Le ressaut hydraulique dans les canaux prismatique à parois rugueuses," Ph.D. dissertation, Université Mohamed Khider-Biskra, Biskra, Algeria, 2012.
M. Debabeche, S. Kateb, and A. Ghomri, "Étude expérimentale du ressaut hydraulique dans un canal triangulaire à parois rugueuses," LARHYSS Journal, vol. 4, no. 1, pp. 187–196, Jun. 2006.
Downloads
How to Cite
License
Copyright (c) 2025 Khechiba Haroun, Ali Ghomri, Djamel Besser, Ibtissam Herri

This work is licensed under a Creative Commons Attribution 4.0 International License.
Authors who publish with this journal agree to the following terms:
- Authors retain the copyright and grant the journal the right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) after its publication in ETASR with an acknowledgement of its initial publication in this journal.