Stabilization of the banks and bed of the river is an important problem in river engineering works. River bed scouring is a major environmental problem for fish and aquatic habitat resources. Using a bed sill is one approach that can be used to prevent waterway bed scouring. In this study, a concave bed sill was tested in an experimental program with movable bed condition. In addition to the experimental program, numerical simulations were undertaken to explore the flow characteristic around concave bed sill. In experiment the results showed that most scouring occurred at the channel sides, while deposition occurred in the middle of channel downstream of the concave bed sill. During the experiment two dimensional flow velocity was measured using particle image velocimetry (PIV). It was found that a vortex formed at the sides and downstream of the concave bed sill and then stretched to the middle of the channel. The results also indicated that there was minimum flow vorticity intensity at the center of the channel where deposition occurred. The numerical results were compared with this experimental data to validate the numerical simulations. The numerical results confirmed that for a concave bed sill, similarly a vortex formed at the side of the channel which created the maximum scouring depth at the side wall and with following deposition of sediment particles in the centerline of the channel.
| Published in | Hydrology (Volume 8, Issue 2) |
| DOI | 10.11648/j.hyd.20200802.12 |
| Page(s) | 26-33 |
| Creative Commons |
This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited. |
| Copyright |
Copyright © The Author(s), 2020. Published by Science Publishing Group |
River Engineering, Concave Bed Sill, Scour, Numerical Model, Vortex
| [1] | M. Ben Meftah and M. Mossa, “Experimental study of the scour hole downstream of bed sills,” in River Flow, M. Greco, A. Carravetta and R. Della Morte Eds., pp. 585-592, 2004. |
| [2] | C. Chinnarasri and D. Kositgittiwong, “Laboratory study of maximum scour depth downstream of sills,” In Proceedings of the Institution of Civil Engineers-Water Management, vol. 161, no. 5, pp. 267-275, 2008. |
| [3] | R. Gaudio and A. Marion, “Time evolution of scouring downstream of bed sills,” Journal of Hydraulic Research, vol. 41, no. 3, pp. 271-284, 2003. |
| [4] | R. Gaudio, A. Marion and V. Bovoli, “Morphological effects of bed sills in degrading rivers,” Journal of Hydraulic Research, 38 (2), pp. 89-96, 2000. |
| [5] | D. Guan, B. Melville, and H. Friedrich, “Flow patterns and turbulence structures in a scour hole downstream of a submerged weir,” Journal of Hydraulic Engineering 140.1, pp. 68-76, 2014. |
| [6] | D. Guan, B. Melville and H. Friedrich, “Local scour at submerged weirs in sand-bed channels,” Journal of Hydraulic Research, vol. 54, no. 2, pp. 172-184, 2016. |
| [7] | H. Hamidifar, M. Nasrabadi, and M. H. Omid, “Using a bed sill as a scour countermeasure downstream of an apron,” Ain Shams Engineering Journal 9.4, pp. 1663-1669, 2018. |
| [8] | H. Hamidifar, M. H. Omid, and M. Nasrabadi, “Reduction of scour using a combination of riprap and bed sill,” Proceedings of the Institution of Civil Engineers-Water Management. Vol. 171. No. 5. Thomas Telford Ltd, 2018. |
| [9] | A. Keshavarzi and L. Khaje Noori, “Environmental protection stability of river bed and banks using convex, concave, and linear bed sills,” Environmental Monitoring and Assessment, vol. 17, no. 1, pp. 621-631, 2010. |
| [10] | A. Keshavarzi and M. Sohrabi, “Study on the effect of different bed sills on flow structure and scouring at the bed of channel,” Proceedings of the 3rd International Conference on Civil, Structural and Transportation Engineering (ICCSTE'18), Niagara Falls, Canada, June 10–12, 2018. |
| [11] | A. Keshavarzi, R. Gazni, and R. Homayoon, “Prediction of scouring around an arch-shaped bed sill using neuro-fuzzy model,” Applied Soft Computing, vol. 12, pp. 486–493, 2012. |
| [12] | M. A. Lenzi, A., Marion, Comiti, F and R. Gaudio, “Local scouring in low and high gradient streams at bed sills,” Journal of Hydraulic Research, IAHR, vol. 40, no. 6, pp. 731-739, 2002. |
| [13] | J. Y. Lu, J. H. Hong, K. P. Chang, and T. F. Lu, “Evolution of scouring process downstream of grade-control structures under steady and unsteady flows,” Hydrological Processes 27.19, pp. 2699-2709, 2013. |
| [14] | M. Sohrabi, A. Keshavarzi, and M. Javan, “Impact of Bed Sill Shapes on Scour Protection in River Bed and Banks,” International Journal of River Basin Management 17.3, pp. 277-287, 2018. |
| [15] | M. Tregnaghi, “Local scouring at bed sills under steady and unsteady conditions,” Ph. D. Thesis, University of Padova: 161, 2008. |
| [16] | M. Tregnaghi, A. Marion, A. Bottacin-Busolin, and S. J. Tait, “Modelling time varying scouring at bed sills,” Earth Surface Processes and Landforms 36.13, pp. 1761-1769, 2011. |
APA Style
Moslem Sohrabi, Alireza Keshavarzi, Mahmood Javan. (2020). A Study of Flow Structure Topology in the Vicinity of a Concave Bed Sill Using Numerical Model. Hydrology, 8(2), 26-33. https://doi.org/10.11648/j.hyd.20200802.12
ACS Style
Moslem Sohrabi; Alireza Keshavarzi; Mahmood Javan. A Study of Flow Structure Topology in the Vicinity of a Concave Bed Sill Using Numerical Model. Hydrology. 2020, 8(2), 26-33. doi: 10.11648/j.hyd.20200802.12
AMA Style
Moslem Sohrabi, Alireza Keshavarzi, Mahmood Javan. A Study of Flow Structure Topology in the Vicinity of a Concave Bed Sill Using Numerical Model. Hydrology. 2020;8(2):26-33. doi: 10.11648/j.hyd.20200802.12
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Download@article{10.11648/j.hyd.20200802.12,
author = {Moslem Sohrabi and Alireza Keshavarzi and Mahmood Javan},
title = {A Study of Flow Structure Topology in the Vicinity of a Concave Bed Sill Using Numerical Model},
journal = {Hydrology},
volume = {8},
number = {2},
pages = {26-33},
doi = {10.11648/j.hyd.20200802.12},
url = {https://doi.org/10.11648/j.hyd.20200802.12},
eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.hyd.20200802.12},
abstract = {Stabilization of the banks and bed of the river is an important problem in river engineering works. River bed scouring is a major environmental problem for fish and aquatic habitat resources. Using a bed sill is one approach that can be used to prevent waterway bed scouring. In this study, a concave bed sill was tested in an experimental program with movable bed condition. In addition to the experimental program, numerical simulations were undertaken to explore the flow characteristic around concave bed sill. In experiment the results showed that most scouring occurred at the channel sides, while deposition occurred in the middle of channel downstream of the concave bed sill. During the experiment two dimensional flow velocity was measured using particle image velocimetry (PIV). It was found that a vortex formed at the sides and downstream of the concave bed sill and then stretched to the middle of the channel. The results also indicated that there was minimum flow vorticity intensity at the center of the channel where deposition occurred. The numerical results were compared with this experimental data to validate the numerical simulations. The numerical results confirmed that for a concave bed sill, similarly a vortex formed at the side of the channel which created the maximum scouring depth at the side wall and with following deposition of sediment particles in the centerline of the channel.},
year = {2020}
}
TY - JOUR T1 - A Study of Flow Structure Topology in the Vicinity of a Concave Bed Sill Using Numerical Model AU - Moslem Sohrabi AU - Alireza Keshavarzi AU - Mahmood Javan Y1 - 2020/08/31 PY - 2020 N1 - https://doi.org/10.11648/j.hyd.20200802.12 DO - 10.11648/j.hyd.20200802.12 T2 - Hydrology JF - Hydrology JO - Hydrology SP - 26 EP - 33 PB - Science Publishing Group SN - 2330-7617 UR - https://doi.org/10.11648/j.hyd.20200802.12 AB - Stabilization of the banks and bed of the river is an important problem in river engineering works. River bed scouring is a major environmental problem for fish and aquatic habitat resources. Using a bed sill is one approach that can be used to prevent waterway bed scouring. In this study, a concave bed sill was tested in an experimental program with movable bed condition. In addition to the experimental program, numerical simulations were undertaken to explore the flow characteristic around concave bed sill. In experiment the results showed that most scouring occurred at the channel sides, while deposition occurred in the middle of channel downstream of the concave bed sill. During the experiment two dimensional flow velocity was measured using particle image velocimetry (PIV). It was found that a vortex formed at the sides and downstream of the concave bed sill and then stretched to the middle of the channel. The results also indicated that there was minimum flow vorticity intensity at the center of the channel where deposition occurred. The numerical results were compared with this experimental data to validate the numerical simulations. The numerical results confirmed that for a concave bed sill, similarly a vortex formed at the side of the channel which created the maximum scouring depth at the side wall and with following deposition of sediment particles in the centerline of the channel. VL - 8 IS - 2 ER -
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