Energy Dissipation in Drop Manhole Cascades
Publication: Journal of Irrigation and Drainage Engineering
Volume 150, Issue 5
Abstract
Drop manholes are hydraulic devices typically employed to dissipate flow energy in high slope, urban drainage systems. The use of several drops of small height placed in series (drop manhole cascade) is a more economical and effective method for controlling velocity and kinetic energy than a single drop of large height. An experimental campaign was specifically designed to investigate hydraulics of drop manhole cascades at the LIA Laboratory, University of Cassino and Southern Lazio. Results were summarized in equations that quantify overall dissipation performance and describe the hydraulics of the downstream flow in terms of outflow depth and energy head. The performance of single drops and a three-drop cascade are compared. The data show how the energy of the stream passing through the dropshaft cascade quickly achieves a new equilibrium condition downstream from the second manhole. Finally, the energy dissipation of a drop manhole cascade was compared with that of smooth and roughened chutes to highlight similarities and differences between different dissipation structures.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
All data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
The authors thank eng. Francesco Bisecco who helped carry out the experiments, three anonymous reviewers, and the editors for comments and suggestions that helped improve the paper.
References
Bathurst, J. C. 1978. “Flow resistance of large-scale roughness.” J. Hydraul. Div. 104 (12): 1587–1603. https://doi.org/10.1061/JYCEAJ.0005114.
Camino, G. A., D. Z. Zhu, and N. Rajaratnam. 2011. “Hydraulics of stacked drop manholes.” J. Irrig. Drain. Eng. 137 (8): 537–552. https://doi.org/10.1061/(ASCE)IR.1943-4774.0000327.
Camino, G. A., D. Z. Zhu, N. Rajaratnam, and M. Shome. 2009. “Use of a stacked drop manhole for energy dissipation: A case study in Edmonton, Alberta.” Can. J. Civ. Eng. 36 (6): 1037–1050. https://doi.org/10.1139/L09-036.
Carvalho, R. F., and J. Leandro. 2012. “Hydraulic characteristics of a drop square manhole with a downstream control gate.” J. Irrig. Drain. Eng. 138 (6): 569–576. https://doi.org/10.1061/(ASCE)IR.1943-4774.0000437.
Chan, S. N., C. L. Troy, D. Z. Zhu, and J. H. W. Lee. 2023. “Vortex-intake drop structures.” In Chapter 5 of vortex-flow intakes—IAHR water monographs, 61–86. Madrid, Spain: International Association for Hydro-Environment Engineering and Research.
Chanson, H. 2000. “Hydraulics of roman aqueducts: Steep chutes, cascades, and dropshafts.” Am. J. Archaeol. 104 (1): 47–72. https://doi.org/10.2307/506792.
Chanson, H. 2002. “An experimental study of Roman dropshaft hydraulics.” J. Hydraul. Res. 40 (1): 3–12. https://doi.org/10.1080/00221680209499868.
Chanson, H. 2004. “Hydraulics of rectangular dropshafts.” J. Irrig. Drain. Eng. 130 (6): 523–529. https://doi.org/10.1061/(ASCE)0733-9437(2004)130:6(523).
Christodoulou, G. C. 1991. “Drop manholes in supercritical pipelines.” J. Irrig. Drain. Eng. 117 (1): 37–47. https://doi.org/10.1061/(ASCE)0733-9437(1991)117:1(37).
Del Giudice, G., and C. Gisonni. 2011. “Vortex dropshaft retrofitting: Case of Naples City (Italy).” J. Hydraul. Res. 49 (6): 804–808. https://doi.org/10.1080/00221686.2011.622148.
Del Giudice, G., C. Gisonni, and W. H. Hager. 2000. “Supercritical flow in bend manhole.” J. Irrig. Drain. Eng. 126 (1): 48–56. https://doi.org/10.1061/(ASCE)0733-9437(2000)126:1(48).
Drioli, C. 1947. “Su un particolare tipo di imbocco per pozzi di scarico (On a particular intake for overflow dropshafts).” L’Energia Elettrica 24 (10): 447–452.
Ferro, V. 1999. “Friction factor for gravel-bed channel with high boulder concentration.” J. Hydraul. Eng. 125 (7): 771–778. https://doi.org/10.1061/(ASCE)0733-9429(1999)125:7(771).
Frits, H. M., and W. H. Hager. 1998. “Hydraulics of embankment weirs.” J. Hydraul. Eng. 124 (9): 963–971.
Gargano, R., and W. H. Hager. 2002. “Supercritical flow across sewer manholes.” J. Hydraul. Eng. 128 (11): 1014–1017. https://doi.org/10.1061/(ASCE)0733-9429(2002)128:11(1014).
Gisonni, C., and W. H. Hager. 2002. “Supercritical flow in manholes with a bend extension.” Exp. Fluids 32 (3): 357–365. https://doi.org/10.1007/s003480100364.
Granata, F. 2016. “Dropshaft cascades in urban drainage systems.” Water Sci. Technol. 73 (9): 2052–2059. https://doi.org/10.2166/wst.2016.051.
Granata, F., G. De Marinis, and R. Gargano. 2012. “Criteri per il dimensionamento dei pozzetti di salto circolari (Criteria for the sizing of circular drop manholes).” L’Acqua 90 (2): 9–20.
Granata, F., G. De Marinis, R. Gargano, and W. H. Hager. 2011. “Hydraulics of circular drop manholes.” J. Irrig. Drain. Eng. 137 (2): 102–111. https://doi.org/10.1061/(ASCE)IR.1943-4774.0000279.
Hager, W. H. 1990. “Vortex drop inlet for supercritical approaching flow.” J. Hydraul. Eng. 116 (8): 1048–1054. https://doi.org/10.1061/(ASCE)0733-9429(1990)116:8(1048).
Hager, W. H. 2010. Wastewater hydraulics theory and practice. 2nd ed. Berlin: Springer.
Ma, Y., D. Z. Zhu, N. Rajaratnam, and B. van Duin. 2017. “Energy dissipation in circular drop manholes.” J. Irrig. Drain. Eng. 143 (12): 04017047. https://doi.org/10.1061/(ASCE)IR.1943-4774.0001241.
Odgaard, A. J., T. C. Lyons, and A. J. Craig. 2013. “Baffle-drop structure design relationships.” J. Hydraul. Eng. 139 (9): 995–1002. https://doi.org/10.1061/(ASCE)HY.1943-7900.0000761.
Pagliara, S., and P. Chiavaccini. 2006. “Energy dissipation on block ramps.” J. Hydraul. Eng. 132 (1): 41–48. https://doi.org/10.1061/(ASCE)0733-9429(2006)132:1(41).
Pagliara, S., R. Das, and P. Palermo. 2008. “Energy dissipation on submerged block ramps.” J. Irrig. Drain. Eng. 134 (4): 527–532. https://doi.org/10.1061/(ASCE)0733-9437(2008)134:4(527).
Peruginelli, A., and S. Pagliara. 2000. “Energy dissipation comparison among stepped channel, drop and ramp structures.” In Proc., Int. Workshop on Hydraulics of Stepped Spillways, 111–118. London: Taylor & Francis.
Rajaratnam, N., A. Mainali, and C. Y. Hsung. 1997. “Observations on flow in vertical dropshafts in urban drainage systems.” J. Environ. Eng. 123 (5): 486–491. https://doi.org/10.1061/(ASCE)0733-9372(1997)123:5(486).
Skipworth, P. J., S. J. Tait, and J. S. Adrian. 1999. “Erosion of sediment beds in sewers: Model development.” J. Environ. Eng. 125 (6): 566–573. https://doi.org/10.1061/(ASCE)0733-9372(1999)125:6(566).
White, M. P. 1943. “Energy loss at the base of a free overfall. Discussion.” Trans. ASCE 108: 1361–1364.
Yang, Q., and Q. Yang. 2021. “Numerical investigation of the turbulence characteristics and energy dissipation mechanism of baffle drop shafts.” Water Sci. Technol. 83 (9): 2259–2270. https://doi.org/10.2166/wst.2021.137.
Zheng, F., Y. Li, J. Zhao, and J. An. 2017. “Energy dissipation in circular drop manholes under different outflow conditions.” Water 9 (10): 752. https://doi.org/10.3390/w9100752.
Information & Authors
Information
Published In
Journal of Irrigation and Drainage Engineering
Volume 150 • Issue 5 • October 2024
Copyright
© 2024 American Society of Civil Engineers.
History
Received: Sep 13, 2023
Accepted: Mar 21, 2024
Published online: Jul 2, 2024
Published in print: Oct 1, 2024
Discussion open until: Dec 2, 2024
ASCE Technical Topics:
- Bodies of water (by type)
- Channels (waterway)
- Coasts, oceans, ports, and waterways engineering
- Design (by type)
- Drainage
- Drainage systems
- Energy dissipation
- Engineering fundamentals
- Engineering mechanics
- Geomechanics
- Geotechnical engineering
- Hydraulic design
- Hydraulic engineering
- Hydraulic structures
- Hydraulics
- Infrastructure
- Irrigation engineering
- Lifeline systems
- Maintenance hole
- River engineering
- Sewers
- Slopes
- Stream channels
- Structural engineering
- Structures (by type)
- Thermodynamics
- Water and water resources
- Water management
- Waterways
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.