Surya Murali Racha, Shouvik Mitra, B. Shown, S. Mandal, A. Das
Sustainable supply and utilization of water is required for the global economy and growth. In order to cater the needs, seawater desalination by membrane technique, reverse osmosis (RO), have become more attractive to produce potable water. Despite the potential advantages of RO process, it has limitations like low water recovery, low selectivity, membrane fouling, high energy requirement and brine disposal. Recent progress and developments in membrane materials, membrane modules and processes had laid foundation to novel technologies. Membrane distillation (MD), forward osmosis (FO) and pressure retarded osmosis (PRO) are emerging as niche area of research for seawater desalination. It is noteworthy to mention that advances in FO and MD for desalination allows the entire operation at low hydraulic pressure, which reduces the fouling and improves the membrane life. Whereas PRO is an osmotically driven process that produces the green energy from the brine stream. On the other hand, hybrid desalination processes in combination with RO, emerging technologies and renewable energy sources are found to be efficient compared to stand alone technology with a reduced desalination cost. Although a wide number of literatures are available, but practical integration of current state-of-the-art and its gradual progress is rarely addressed. In this context we represent emerging FO, MD and PRO processes, its principles, development of membranes for energy minimization and improved performance. Various configurations of hybrid processes in combination with renewable energy resources have been evaluated. Significant technological development and emergence of new materials is anticipated to play the pivotal role to make membrane-based desalination technologies more efficient, green, and economical in near future.
{"title":"Emerging membrane technologies for low-cost desalination","authors":"Surya Murali Racha, Shouvik Mitra, B. Shown, S. Mandal, A. Das","doi":"10.1680/jwama.22.00006","DOIUrl":"https://doi.org/10.1680/jwama.22.00006","url":null,"abstract":"Sustainable supply and utilization of water is required for the global economy and growth. In order to cater the needs, seawater desalination by membrane technique, reverse osmosis (RO), have become more attractive to produce potable water. Despite the potential advantages of RO process, it has limitations like low water recovery, low selectivity, membrane fouling, high energy requirement and brine disposal. Recent progress and developments in membrane materials, membrane modules and processes had laid foundation to novel technologies. Membrane distillation (MD), forward osmosis (FO) and pressure retarded osmosis (PRO) are emerging as niche area of research for seawater desalination. It is noteworthy to mention that advances in FO and MD for desalination allows the entire operation at low hydraulic pressure, which reduces the fouling and improves the membrane life. Whereas PRO is an osmotically driven process that produces the green energy from the brine stream. On the other hand, hybrid desalination processes in combination with RO, emerging technologies and renewable energy sources are found to be efficient compared to stand alone technology with a reduced desalination cost. Although a wide number of literatures are available, but practical integration of current state-of-the-art and its gradual progress is rarely addressed. In this context we represent emerging FO, MD and PRO processes, its principles, development of membranes for energy minimization and improved performance. Various configurations of hybrid processes in combination with renewable energy resources have been evaluated. Significant technological development and emergence of new materials is anticipated to play the pivotal role to make membrane-based desalination technologies more efficient, green, and economical in near future.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"21 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84963546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Quantitative comparison between different schemes of reservoir operation can provide valuable suggestions to decision-making and help to promote new planning tools under changing environment. A full spectrum of the schemes for reservoir operation range from rule-based setup (RBS), single-objective optimization setup (SOS), bi-objective optimization setup (BOS) to many-objective optimization setup (MOS) is considered. The Qinshitan Reservoir, a large reservoir in the southwest of China, is used as a case and the four schemes of reservoir operation are established with similar formulations and are evaluated quantitatively under typical hydrological years. For the considered optimization problem, progressive improvement on the solutions is obtained from RBS to SOS, then BOS and finally MOS. Amongst the models, the MOS provided a comprehensive perspective on reservoir operation and achieved the best performance for offering the most options to the decision making. The MOS also discovers a step-wise operational scheme that has not been captured by the RBS, the SOS and the BOS.
{"title":"Evaluation of schemes for reservoir operation: from rule-curve to many-objective optimization","authors":"Duan Chen, Arturo Leon, Ruonan Li, Rui Han","doi":"10.1680/jwama.21.00022a","DOIUrl":"https://doi.org/10.1680/jwama.21.00022a","url":null,"abstract":"Quantitative comparison between different schemes of reservoir operation can provide valuable suggestions to decision-making and help to promote new planning tools under changing environment. A full spectrum of the schemes for reservoir operation range from rule-based setup (RBS), single-objective optimization setup (SOS), bi-objective optimization setup (BOS) to many-objective optimization setup (MOS) is considered. The Qinshitan Reservoir, a large reservoir in the southwest of China, is used as a case and the four schemes of reservoir operation are established with similar formulations and are evaluated quantitatively under typical hydrological years. For the considered optimization problem, progressive improvement on the solutions is obtained from RBS to SOS, then BOS and finally MOS. Amongst the models, the MOS provided a comprehensive perspective on reservoir operation and achieved the best performance for offering the most options to the decision making. The MOS also discovers a step-wise operational scheme that has not been captured by the RBS, the SOS and the BOS.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"97 1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76288922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Kabiri-Samani, Nooshin Jafarinasab, Z. S. Khozani
Model experiments were carried out into the hydraulic characteristics of air−water two-phase flow inside the bottom outlet of shaft spillways as a result of natural air suction from air-core vortices at the pipe intake. Experiments were performed in a cylindrical reservoir 2 m in diameter and 1 m high, under a swirling flow around the intake, investigating the most severe two-phase flow regimes. Vertical pipe intakes with three different diameters and heights, attached to the floor of the reservoir at its centre, were examined for different flow discharges by establishing different vortex types. The results including tangential velocity profiles inside the main reservoir, head−discharge relationships, average internal pressure inside the outlet pipe and the relation between swirling flow at the pipe intake and the two-phase flow inside the bottom outlet are discussed in this paper. Results indicate that the void fraction decreases by changing the type of swirling flow. For a constant submergence depth, reducing the intake pipe diameter or increasing its height lead to an increase in void fraction and two-phase slug flow wave Froude number, velocity, length and frequency. However, by the increase in Kolf number, the frequency of slug waves reduced and the average relative two-phase flow pressure inside the bottom outlet was increased. The relationships between two-phase flow hydraulic characteristics and regimes inside the bottom outlet and types of vortices at the intakes will be of the interest of both the scientific research and design engineers, helping them increase the efficiency and safety of pressurised waterway systems.
{"title":"Relationship between two-phase flow in bottom outlet and air-core vortices at intake","authors":"A. Kabiri-Samani, Nooshin Jafarinasab, Z. S. Khozani","doi":"10.1680/jwama.21.00055","DOIUrl":"https://doi.org/10.1680/jwama.21.00055","url":null,"abstract":"Model experiments were carried out into the hydraulic characteristics of air−water two-phase flow inside the bottom outlet of shaft spillways as a result of natural air suction from air-core vortices at the pipe intake. Experiments were performed in a cylindrical reservoir 2 m in diameter and 1 m high, under a swirling flow around the intake, investigating the most severe two-phase flow regimes. Vertical pipe intakes with three different diameters and heights, attached to the floor of the reservoir at its centre, were examined for different flow discharges by establishing different vortex types. The results including tangential velocity profiles inside the main reservoir, head−discharge relationships, average internal pressure inside the outlet pipe and the relation between swirling flow at the pipe intake and the two-phase flow inside the bottom outlet are discussed in this paper. Results indicate that the void fraction decreases by changing the type of swirling flow. For a constant submergence depth, reducing the intake pipe diameter or increasing its height lead to an increase in void fraction and two-phase slug flow wave Froude number, velocity, length and frequency. However, by the increase in Kolf number, the frequency of slug waves reduced and the average relative two-phase flow pressure inside the bottom outlet was increased. The relationships between two-phase flow hydraulic characteristics and regimes inside the bottom outlet and types of vortices at the intakes will be of the interest of both the scientific research and design engineers, helping them increase the efficiency and safety of pressurised waterway systems.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"13 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84325294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Meandering channels widely exist in natural rivers, especially in lowland alluvial plains. In this research, a meandering channel is designed, in order to explore the effect of sediment supply on flow characteristics in it. In this channel, the water level, three-dimensional instantaneous velocity, and riverbed elevation are measured by digital wave altimeter, three-dimensional acoustic Doppler velocimeter (ADV) and three-dimensional laser scanner, respectively; and the flow characteristics with (first case) and without sediment (second case) supply are compared. The results showed that under the same discharge, the transversal slope of water surface in the first case is larger than the second case, and its change is steeper; the longitudinal change degree of water surface in the upper half bend is small, and that is large in the lower half bend. By increasing the water discharge, the number of secondary flow vortices at the apex of meandering channel is increased. The trend of the two mainstream lines, with and without sediment supply, are roughly opposite, and the difference between them decreases with increasing the discharge. In addition, the lateral and vertical turbulence intensity of the flow near the outer bank are larger under the two cases. The turbulent kinetic energy of the cross-section is larger in the first case near the bed and water surface.
{"title":"Effect of sediment supply on flow characteristics in a meandering channel","authors":"Hao Zheng, Yunwen Pan, Kejun Yang","doi":"10.1680/jwama.22.00039","DOIUrl":"https://doi.org/10.1680/jwama.22.00039","url":null,"abstract":"Meandering channels widely exist in natural rivers, especially in lowland alluvial plains. In this research, a meandering channel is designed, in order to explore the effect of sediment supply on flow characteristics in it. In this channel, the water level, three-dimensional instantaneous velocity, and riverbed elevation are measured by digital wave altimeter, three-dimensional acoustic Doppler velocimeter (ADV) and three-dimensional laser scanner, respectively; and the flow characteristics with (first case) and without sediment (second case) supply are compared. The results showed that under the same discharge, the transversal slope of water surface in the first case is larger than the second case, and its change is steeper; the longitudinal change degree of water surface in the upper half bend is small, and that is large in the lower half bend. By increasing the water discharge, the number of secondary flow vortices at the apex of meandering channel is increased. The trend of the two mainstream lines, with and without sediment supply, are roughly opposite, and the difference between them decreases with increasing the discharge. In addition, the lateral and vertical turbulence intensity of the flow near the outer bank are larger under the two cases. The turbulent kinetic energy of the cross-section is larger in the first case near the bed and water surface.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"23 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73460098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sustainable use of water reservoirs is threatened by sediment accumulation. The loss of storage volume can be prevented or limited by appropriate sediment management strategies that work for a variety of expected conditions. The paper presents the development of a reservoir flushing strategy, tested against water and sediment inflow that might occur over the centuries. A typical length of water and sediment record of 50 years to represent the range of variability within a year is used and extended by deducing longer term inter-annual variability from suitable indicators (sediment cores in natural lakes, tree-ring chronologies, etc.) It was concluded that over the past centuries, water inflows in a period of 50 years could typically vary by about 10% while sediment inflows could vary by about 20%. The resilience of flushing rules derived solely on the recorded data set over centuries-long periods was tested using a long-term computer simulation of reservoir sedimentation. The simulations showed that some modifications to the rule would increase its performance over centuries-long period. Although the approach was derived for a specific project, it is based on some generally applicable parameters such as the discharge at which operation stops and moving average of the annual peak flow.
{"title":"Adapting reservoir flushing strategies to changing hydro-climatic conditions","authors":"G. Petkovšek","doi":"10.1680/jwama.22.00020","DOIUrl":"https://doi.org/10.1680/jwama.22.00020","url":null,"abstract":"Sustainable use of water reservoirs is threatened by sediment accumulation. The loss of storage volume can be prevented or limited by appropriate sediment management strategies that work for a variety of expected conditions. The paper presents the development of a reservoir flushing strategy, tested against water and sediment inflow that might occur over the centuries. A typical length of water and sediment record of 50 years to represent the range of variability within a year is used and extended by deducing longer term inter-annual variability from suitable indicators (sediment cores in natural lakes, tree-ring chronologies, etc.) It was concluded that over the past centuries, water inflows in a period of 50 years could typically vary by about 10% while sediment inflows could vary by about 20%. The resilience of flushing rules derived solely on the recorded data set over centuries-long periods was tested using a long-term computer simulation of reservoir sedimentation. The simulations showed that some modifications to the rule would increase its performance over centuries-long period. Although the approach was derived for a specific project, it is based on some generally applicable parameters such as the discharge at which operation stops and moving average of the annual peak flow.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"47 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74885372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Priyanka Gautam, T. Eldho, B. S. Mazumder, M. Behera
The objective of this study is to explore the higher-order turbulence statistics of flow and turbulent length scales around a complex pier (CP) and compare the results with that of a simple pier (SP). The velocity data were recorded in a laboratory flume using Particle Image Velocimetry (PIV). The PIV data were analyzed to estimate the velocity fluctuations of third-order, turbulence production, and dissipation rates, turbulent length scales and the contributions of burst-sweep events to the total Reynolds shear stress around the piers mounted on a rigid flat surface. The skewness and advection coefficients indicate a more asymmetric distribution of velocity fluctuations for SP than that of CP. The ejection and sweep events illustrate the dominance of similar strengths for an extended period, downstream of the piers. The upstream TKE production was similar for both the piers, while the upstream dissipation rate is higher for CP than SP. The length scales show greater values at the upstream and lower values at the downstream of SP than CP. The findings show the importance of the pile-cap in restricting the downward moving flow by showing a lower magnitude of scour-causing turbulence parameters for CP than SP.
{"title":"Higher-order turbulence around simple and complex piers using Particle Image Velocimetry","authors":"Priyanka Gautam, T. Eldho, B. S. Mazumder, M. Behera","doi":"10.1680/jwama.22.00017","DOIUrl":"https://doi.org/10.1680/jwama.22.00017","url":null,"abstract":"The objective of this study is to explore the higher-order turbulence statistics of flow and turbulent length scales around a complex pier (CP) and compare the results with that of a simple pier (SP). The velocity data were recorded in a laboratory flume using Particle Image Velocimetry (PIV). The PIV data were analyzed to estimate the velocity fluctuations of third-order, turbulence production, and dissipation rates, turbulent length scales and the contributions of burst-sweep events to the total Reynolds shear stress around the piers mounted on a rigid flat surface. The skewness and advection coefficients indicate a more asymmetric distribution of velocity fluctuations for SP than that of CP. The ejection and sweep events illustrate the dominance of similar strengths for an extended period, downstream of the piers. The upstream TKE production was similar for both the piers, while the upstream dissipation rate is higher for CP than SP. The length scales show greater values at the upstream and lower values at the downstream of SP than CP. The findings show the importance of the pile-cap in restricting the downward moving flow by showing a lower magnitude of scour-causing turbulence parameters for CP than SP.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"82 1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80066535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
By the drainage-area ratio method, the daily or monthly flows gauged at a nearby station are transferred to an ungauged section where a dam is to be built by multiplying them by the real number resulting from raising the ratio of the drainage areas of the dam section and of the station to an exponent (n). Commonly n is taken as 1. First, using the daily flows of two stations nearby the dam section on the same stream or on a neighboring stream, having a common N-year long gauging record, it is proposed that 365 linear regressions be fitted to N pairs of 365 daily flows, and relating them to the drainage area ratios, daily flows at the dam section be computed using 365 n's each belonging to a day. Next, by the same analytical model applied to the monthly flows, 12 monthly flows are transferred to the dam section. Five versions of the drainage-area ratio method, three of which with constant exponents, are investigated, and the last one with n = 1 is found to be relatively the worst.
{"title":"A few versions of the drainage-area ratio method for transfer of daily or monthly stream flows","authors":"T. Haktanir, A. Aydemir, Nese Acanal","doi":"10.1680/jwama.21.00091","DOIUrl":"https://doi.org/10.1680/jwama.21.00091","url":null,"abstract":"By the drainage-area ratio method, the daily or monthly flows gauged at a nearby station are transferred to an ungauged section where a dam is to be built by multiplying them by the real number resulting from raising the ratio of the drainage areas of the dam section and of the station to an exponent (n). Commonly n is taken as 1. First, using the daily flows of two stations nearby the dam section on the same stream or on a neighboring stream, having a common N-year long gauging record, it is proposed that 365 linear regressions be fitted to N pairs of 365 daily flows, and relating them to the drainage area ratios, daily flows at the dam section be computed using 365 n's each belonging to a day. Next, by the same analytical model applied to the monthly flows, 12 monthly flows are transferred to the dam section. Five versions of the drainage-area ratio method, three of which with constant exponents, are investigated, and the last one with n = 1 is found to be relatively the worst.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"22 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72842754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-01DOI: 10.1680/jwama.2023.176.1.51
{"title":"<i>Water Management</i>: Referees 2022","authors":"","doi":"10.1680/jwama.2023.176.1.51","DOIUrl":"https://doi.org/10.1680/jwama.2023.176.1.51","url":null,"abstract":"","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136362586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-01DOI: 10.1680/jwama.2023.176.1.50
{"title":"Award-winning paper in 2021","authors":"","doi":"10.1680/jwama.2023.176.1.50","DOIUrl":"https://doi.org/10.1680/jwama.2023.176.1.50","url":null,"abstract":"","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136362587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The occurrence of scour around bridge elements by the transportation of bed material during flood events can cause serious structural damages and loss of lives. Furthermore, increased uncertainty of precipitation and runoff prediction due to climate change makes this phenomenon more complex and dangerous nowadays. So, bridge scour countermeasures should be more focused on decreasing scour formation around bridge elements. In this study, abutment scour under clear-water conditions with constant flow intensity was conducted and collars were tested as scour countermeasures around semi-circular end bridge abutments. The experimental study was performed in a rectangular channel with an almost uniform cohesionless bed material for 3 h with and without collars. Collars of various lengths located at different elevations around the abutments were tested to investigate the effect of collars on scour development. Based on the experimental results of the study, it was concluded that scour depths decreased with increasing collar width and the collar was placed below the bed level for a given abutment length. The results of this study were compared with those of similar earlier studies to show the effect of abutment shape, size of the bed sediment and test durations on the development of scour depth around the abutments.
{"title":"Effects of collars on local scour around semi-circular end bridge abutments","authors":"M. Gogus, Sueyla Daskin, Serkan Gokmener","doi":"10.1680/jwama.21.00011","DOIUrl":"https://doi.org/10.1680/jwama.21.00011","url":null,"abstract":"The occurrence of scour around bridge elements by the transportation of bed material during flood events can cause serious structural damages and loss of lives. Furthermore, increased uncertainty of precipitation and runoff prediction due to climate change makes this phenomenon more complex and dangerous nowadays. So, bridge scour countermeasures should be more focused on decreasing scour formation around bridge elements. In this study, abutment scour under clear-water conditions with constant flow intensity was conducted and collars were tested as scour countermeasures around semi-circular end bridge abutments. The experimental study was performed in a rectangular channel with an almost uniform cohesionless bed material for 3 h with and without collars. Collars of various lengths located at different elevations around the abutments were tested to investigate the effect of collars on scour development. Based on the experimental results of the study, it was concluded that scour depths decreased with increasing collar width and the collar was placed below the bed level for a given abutment length. The results of this study were compared with those of similar earlier studies to show the effect of abutment shape, size of the bed sediment and test durations on the development of scour depth around the abutments.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"22 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79030739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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