Urban pluvial floods can be produced or exacerbated by insufficient inlets density or by their poor hydraulic efficiency. A proper regard on inlet hydraulic performance is essential to guarantee the correct functioning of urban drainage systems during heavy storm events. The recent advances in computation analysis in the field of hydrodynamics modelling allow to use the well-known concept of dual drainage for design and planning purposes simulating flow transfers between surface layer (street) and underground layer (sewer) through a proper hydraulic characterization of inlet efficiency. Currently, powerful commercial software packages allow the simulation of flow transferring including different approaches and formulas. Many of these approaches include the possibility to treat sewer inlets as an orifice. In this context, this paper presents a methodology to obtain orifice discharge coefficients for three inlets previously tested at the Hydraulic Laboratory of the Technical University of Catalonia. Obtained results show discharge coefficient values between 0,18 and 0,58 with a Froude number between 1.12 and 4.4, quite far from usual recommended values. The procedure can be applied even to non-tested grates.
{"title":"Discharge coefficients to be used in inlet hydraulics","authors":"M. Gómez, J. Tellez-Álvarez, B. Russo","doi":"10.1680/jwama.22.00059","DOIUrl":"https://doi.org/10.1680/jwama.22.00059","url":null,"abstract":"Urban pluvial floods can be produced or exacerbated by insufficient inlets density or by their poor hydraulic efficiency. A proper regard on inlet hydraulic performance is essential to guarantee the correct functioning of urban drainage systems during heavy storm events. The recent advances in computation analysis in the field of hydrodynamics modelling allow to use the well-known concept of dual drainage for design and planning purposes simulating flow transfers between surface layer (street) and underground layer (sewer) through a proper hydraulic characterization of inlet efficiency. Currently, powerful commercial software packages allow the simulation of flow transferring including different approaches and formulas. Many of these approaches include the possibility to treat sewer inlets as an orifice. In this context, this paper presents a methodology to obtain orifice discharge coefficients for three inlets previously tested at the Hydraulic Laboratory of the Technical University of Catalonia. Obtained results show discharge coefficient values between 0,18 and 0,58 with a Froude number between 1.12 and 4.4, quite far from usual recommended values. The procedure can be applied even to non-tested grates.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"15 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78175614","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}
Fernanda Dias Radesca, Matheus Martins de Sousa, Aline Pires Veról, Laurent Feu Grancer Silva Oliveira, João Paulo Rebechi Fraga, Paulo Canedo de Magalhães, Marcelo Gomes Miguez
The use of dual-drainage models has increased in recent decades, mostly because of advances in mathematical methods and geographic information system tools. This type of modelling provides precise diagnoses and can be applied to evaluate stormwater infrastructure and diverse drainage alternatives. Minor and major drainage relations in the Dona Eugênia watershed, Brazil, were analysed in this study. Three alternatives simulated the quasi-two-dimensional hydrodynamic model Modcel. The first alternative considered only the terrain surface layer, representing the current situation. In the second alternative, a layer containing a designed storm sewer was introduced. Considering the previous alternatives as a way to diagnose the main minor and major deficiencies, a third alternative was formulated considering previous projects to solve floods in the watershed, incorporating them in the second alternative with functional minor drainage. The results identified the locations of minor drainage gaps, thus helping to direct efforts to the most critical regions, optimise operations and minimise maintenance costs. The results could also be used to evaluate the effects of storm sewer network discharges in major drainage systems, leading to better design of the drainage infrastructure. The major drainage itself can be optimised, once its responsibility in flooding is identified.
{"title":"Multilayer modelling as a support tool for flood diagnosis and drainage system design","authors":"Fernanda Dias Radesca, Matheus Martins de Sousa, Aline Pires Veról, Laurent Feu Grancer Silva Oliveira, João Paulo Rebechi Fraga, Paulo Canedo de Magalhães, Marcelo Gomes Miguez","doi":"10.1680/jwama.21.00041","DOIUrl":"https://doi.org/10.1680/jwama.21.00041","url":null,"abstract":"The use of dual-drainage models has increased in recent decades, mostly because of advances in mathematical methods and geographic information system tools. This type of modelling provides precise diagnoses and can be applied to evaluate stormwater infrastructure and diverse drainage alternatives. Minor and major drainage relations in the Dona Eugênia watershed, Brazil, were analysed in this study. Three alternatives simulated the quasi-two-dimensional hydrodynamic model Modcel. The first alternative considered only the terrain surface layer, representing the current situation. In the second alternative, a layer containing a designed storm sewer was introduced. Considering the previous alternatives as a way to diagnose the main minor and major deficiencies, a third alternative was formulated considering previous projects to solve floods in the watershed, incorporating them in the second alternative with functional minor drainage. The results identified the locations of minor drainage gaps, thus helping to direct efforts to the most critical regions, optimise operations and minimise maintenance costs. The results could also be used to evaluate the effects of storm sewer network discharges in major drainage systems, leading to better design of the drainage infrastructure. The major drainage itself can be optimised, once its responsibility in flooding is identified.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135222536","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}
Estimation of reference crop evapotranspiration (ETo) is very important in planning and scheduling irrigation water. An estimation of ETo by other simple methods is necessary with the loss of one or more meteorological factors required for estimation by the Penmen-Monteith equation. So, the aim of the study was to manage irrigation water in the Al-Baha region of Saudi Arabia using a simple equation to estimate ETo based on air temperature and an effective alternative to the Penmen-Monteith equation (PM). Four simple temperature dependent equations, Thornthwaite, Blaney-Criddle, Hamon and Linacre were selected. The results showed that the Linacre method is the best equation for estimating ETo and although the ETo rate was overestimated based on the Linacre equation compared to PM, it had the lowest error percentage (9.55%) in addition to the highest R2 (0.97). After deducing a new and accurate equation based on the Linacre equation and its high ability to estimate the ETo rate and give it values closest to the results obtained using PM in the Al-Baha region in Saudi Arabia, it can be relied upon to estimate the irrigation needs in the Al-Baha region with irrigation systems used in this region.
{"title":"Management of irrigation water in Al-Baha Region, Saudi Arabia using simple and alternative equation to Penman-Monteith equation","authors":"Khalid Alkhuzai","doi":"10.1680/jwama.23.00012","DOIUrl":"https://doi.org/10.1680/jwama.23.00012","url":null,"abstract":"Estimation of reference crop evapotranspiration (ETo) is very important in planning and scheduling irrigation water. An estimation of ETo by other simple methods is necessary with the loss of one or more meteorological factors required for estimation by the Penmen-Monteith equation. So, the aim of the study was to manage irrigation water in the Al-Baha region of Saudi Arabia using a simple equation to estimate ETo based on air temperature and an effective alternative to the Penmen-Monteith equation (PM). Four simple temperature dependent equations, Thornthwaite, Blaney-Criddle, Hamon and Linacre were selected. The results showed that the Linacre method is the best equation for estimating ETo and although the ETo rate was overestimated based on the Linacre equation compared to PM, it had the lowest error percentage (9.55%) in addition to the highest R2 (0.97). After deducing a new and accurate equation based on the Linacre equation and its high ability to estimate the ETo rate and give it values closest to the results obtained using PM in the Al-Baha region in Saudi Arabia, it can be relied upon to estimate the irrigation needs in the Al-Baha region with irrigation systems used in this region.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"53 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73582171","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}
N. Azizi, Askari Tashakori, E. Maroufpoor, S. Emamgholizadeh
This research intended to measure wetting front advancements (WFA) under various conditions using a physical model. Wetting front advance, along with its distribution in soils, is one of the important parameters in drip irrigation. It is influenced by many factors, including land slope, emitter discharge and soil texture. The effects of these factors were investigated by constructing a physical model with dimensions of 60 cm in width, 120 cm in height and 160 cm in length. The experiments were conducted using two heterogeneous soils, three land slopes (0, 10 and 20%), three emitter discharges (2, 4 and 8 L/h) and a constant volume of irrigation water (24 L). The results of the heterogeneous soils with three horizontal layers were also compared with those of three homogeneous soils (heavy, medium, and light textures). The results indicate that on sloping lands, the wetted area of the WFA downstream from the emitter was, on average, 20–62% greater than upstream from the emitter. With increases in land slope, the wetted depth under the emitter decreased by 3–18%. Also, when land slope changed from 0–10% and then again from 10–20%, the maximum radius of the wetting front increased, on average, by 32%, 44.8% and 77.5% for discharges of 2, 4 and 8 L/h, respectively.
{"title":"Experimental study of the expansion of soil wetting fronts from a point source in heterogeneous sloping lands","authors":"N. Azizi, Askari Tashakori, E. Maroufpoor, S. Emamgholizadeh","doi":"10.1680/jwama.21.00107","DOIUrl":"https://doi.org/10.1680/jwama.21.00107","url":null,"abstract":"This research intended to measure wetting front advancements (WFA) under various conditions using a physical model. Wetting front advance, along with its distribution in soils, is one of the important parameters in drip irrigation. It is influenced by many factors, including land slope, emitter discharge and soil texture. The effects of these factors were investigated by constructing a physical model with dimensions of 60 cm in width, 120 cm in height and 160 cm in length. The experiments were conducted using two heterogeneous soils, three land slopes (0, 10 and 20%), three emitter discharges (2, 4 and 8 L/h) and a constant volume of irrigation water (24 L). The results of the heterogeneous soils with three horizontal layers were also compared with those of three homogeneous soils (heavy, medium, and light textures). The results indicate that on sloping lands, the wetted area of the WFA downstream from the emitter was, on average, 20–62% greater than upstream from the emitter. With increases in land slope, the wetted depth under the emitter decreased by 3–18%. Also, when land slope changed from 0–10% and then again from 10–20%, the maximum radius of the wetting front increased, on average, by 32%, 44.8% and 77.5% for discharges of 2, 4 and 8 L/h, respectively.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"23 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82225551","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}
In this study, formation conditions of maximum and minimum wave-type jumps are experimentally investigated. A total of 110 wave-type jump experiments are carried out. Experiments are conducted for several discharges, supercritical upstream and subcritical downstream water depths, and drop heights. According to the experimental results, the effective parameters on wave-type jumps are the upstream Froude number and the relative drop height. As the classical hydraulic jump equation is not sufficient to define conjugate depths of wave-type flow, empirical equations are presented for defining conjugate depths for both maximum and minimum wave- type jumps for which no sufficient experimental data is present in the available literature, and the agreement between the calculated and measured conjugate depths is found to be good. It is revealed that the value of the lower limit for the upstream Froude number is not constant for the formation of the maximum wave jump, and it depends on the relative drop height. Furthermore, experimental results of this study showed that energy dissipation ratios of maximum and minimum wave-type jumps are equal or larger than those of the classical hydraulic jumps. For this reason, wave-type jumps may be preferred at stilling basins with drops along with A-jumps.
{"title":"Formation conditions of wave-type flows at stilling basins with a drop","authors":"N. Eroğlu, K. Taştan","doi":"10.1680/jwama.22.00077","DOIUrl":"https://doi.org/10.1680/jwama.22.00077","url":null,"abstract":"In this study, formation conditions of maximum and minimum wave-type jumps are experimentally investigated. A total of 110 wave-type jump experiments are carried out. Experiments are conducted for several discharges, supercritical upstream and subcritical downstream water depths, and drop heights. According to the experimental results, the effective parameters on wave-type jumps are the upstream Froude number and the relative drop height. As the classical hydraulic jump equation is not sufficient to define conjugate depths of wave-type flow, empirical equations are presented for defining conjugate depths for both maximum and minimum wave- type jumps for which no sufficient experimental data is present in the available literature, and the agreement between the calculated and measured conjugate depths is found to be good. It is revealed that the value of the lower limit for the upstream Froude number is not constant for the formation of the maximum wave jump, and it depends on the relative drop height. Furthermore, experimental results of this study showed that energy dissipation ratios of maximum and minimum wave-type jumps are equal or larger than those of the classical hydraulic jumps. For this reason, wave-type jumps may be preferred at stilling basins with drops along with A-jumps.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"77 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72638562","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 boundary shear stress is obtained from the continuity and momentum equations in smooth prismatic open channels. Shear stress is a function of gravity, secondary flow, and gradient velocity. In this research, semi-analytical equations were obtained to estimate the average boundary shear stress in smooth rectangular and trapezoidal open channels by 0.5, 1, 1.5 and 2 side slopes using conformal mapping techniques. After dividing the channel cross section into the bed and wall sub-sections, the present study used the method by Guo and Julien (2005) to estimate the average shear stress of the bed and the wall in open channels. For the studied case, by the first shear stress estimation, secondary current and constant eddy viscosity were neglected. After recommending two secondary current and eddy viscosity correction factors, a second approximation well matched the experimental measurements of the average shear stress for all aspect ratios.
{"title":"Semi-analytical method to estimate boundary shear stress in smooth rectangular and trapezoidal open channels","authors":"P. Beygi, Babak Lashkar-Ara","doi":"10.1680/jwama.21.00067","DOIUrl":"https://doi.org/10.1680/jwama.21.00067","url":null,"abstract":"The boundary shear stress is obtained from the continuity and momentum equations in smooth prismatic open channels. Shear stress is a function of gravity, secondary flow, and gradient velocity. In this research, semi-analytical equations were obtained to estimate the average boundary shear stress in smooth rectangular and trapezoidal open channels by 0.5, 1, 1.5 and 2 side slopes using conformal mapping techniques. After dividing the channel cross section into the bed and wall sub-sections, the present study used the method by Guo and Julien (2005) to estimate the average shear stress of the bed and the wall in open channels. For the studied case, by the first shear stress estimation, secondary current and constant eddy viscosity were neglected. After recommending two secondary current and eddy viscosity correction factors, a second approximation well matched the experimental measurements of the average shear stress for all aspect ratios.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"28 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90873620","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 UK has over 35,000 primary, debris and security screens, intended to prevent internal blockage of culverts by debris and/or entry to a hazardous culvert. Historically some screens were constructed with insufficient justification, insufficient area or poor detailing, leading to increased flood risk and unnecessary safety risks to operatives, especially during high river levels. In 2019, CIRIA's Culvert, screen and outfall manual (C786) replaced the Environment Agency Trash and security screen guide and CIRIA Culvert design and operation manual. The manual encourages assessment of the ongoing need for screens and where they cannot be removed, to take a systems approach that considers the wider watercourse and catchment. This paper presents findings from early experience of using the manual on an Environment Agency programme to assess the continuing need for 92 screens in England. Early indications are that avoiding unnecessary screens and removing or modifying existing screens can improve safety, help natural sediment and debris movement along a watercourse, reduce operational expenditure, and support the net zero carbon target and UN SDG 13 (Climate action). It is recognized that every screen is unique and not every situation is covered by guidance. A novel design that reduces flood and/or safety risk can be justified with documented rational analysis.
{"title":"Towards safer, more sustainable debris and security screens","authors":"Amanda Kitchen, J. Benn, R. Cox, P. Welton","doi":"10.1680/jwama.22.00031","DOIUrl":"https://doi.org/10.1680/jwama.22.00031","url":null,"abstract":"The UK has over 35,000 primary, debris and security screens, intended to prevent internal blockage of culverts by debris and/or entry to a hazardous culvert. Historically some screens were constructed with insufficient justification, insufficient area or poor detailing, leading to increased flood risk and unnecessary safety risks to operatives, especially during high river levels. In 2019, CIRIA's Culvert, screen and outfall manual (C786) replaced the Environment Agency Trash and security screen guide and CIRIA Culvert design and operation manual. The manual encourages assessment of the ongoing need for screens and where they cannot be removed, to take a systems approach that considers the wider watercourse and catchment. This paper presents findings from early experience of using the manual on an Environment Agency programme to assess the continuing need for 92 screens in England. Early indications are that avoiding unnecessary screens and removing or modifying existing screens can improve safety, help natural sediment and debris movement along a watercourse, reduce operational expenditure, and support the net zero carbon target and UN SDG 13 (Climate action). It is recognized that every screen is unique and not every situation is covered by guidance. A novel design that reduces flood and/or safety risk can be justified with documented rational analysis.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"211 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88059915","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}
Yifan Yang, Lu Wang, B. Melville, A. Shamseldin, G. Macky
Migrating bedforms in alluvial rivers can exacerbate scour damage instream structures, leading to severe structure failures, which can cause large-scale and long-term issues with fluvial morphology and environment. This study investigates the interaction between scour fluctuation at instream structures and bedform migration based on large datasets from flume experiments. Both typical 2-D (submerged weirs) and 3-D (uniform and complex piers) structures are considered. Two components constitute real-time live-bed scour depth: the dynamic scour amplification ▵ds caused by bedforms, and the local flow-induced baseline scour depth dsNB without bedform (i.e. denoted as NB). ▵ds is the subtraction of mean of maximum live-bed scour depths and dsNB. Results show that, for 2-D structures, the baseline scour depth is negligible (dsNB→0), while the live-bed scour is mainly caused by the approaching bedform. The dynamic scour amplification normalized by the approaching bedform height (▵ds/Hb) varies between 0.5∼2 depending on the upstream angle. Specifically, ▵ds/Hb decreases with the increase of upstream. For uniform 3-D structures, the local flow could cause a considerable baseline scour depth, and ▵ds/Hb varies between 0.25∼0.5 and decreases with an increase in the flow capacity to deform and damp the approaching bedforms. For complex 3-D structures (e.g. complex piers), the flow pressurisation beneath the structural components (e.g. pile-caps) could magnify ▵ds/Hb to near 1. Summarising experimental data shows that ▵ds/Hb is inversely correlated with ds_NB/y0, where y0 is flow depth. Finally, new equations are proposed for estimating the dynamic scour amplification at various instream structures with design rules recommended. This study, by the first time, enables the understanding of the time-sensitive scour amplification at multiple instream structures from a non-static perspective.
{"title":"Responses of live-bed scour at instream structures to fluvial bedform migration","authors":"Yifan Yang, Lu Wang, B. Melville, A. Shamseldin, G. Macky","doi":"10.1680/jwama.22.00057","DOIUrl":"https://doi.org/10.1680/jwama.22.00057","url":null,"abstract":"Migrating bedforms in alluvial rivers can exacerbate scour damage instream structures, leading to severe structure failures, which can cause large-scale and long-term issues with fluvial morphology and environment. This study investigates the interaction between scour fluctuation at instream structures and bedform migration based on large datasets from flume experiments. Both typical 2-D (submerged weirs) and 3-D (uniform and complex piers) structures are considered. Two components constitute real-time live-bed scour depth: the dynamic scour amplification ▵ds caused by bedforms, and the local flow-induced baseline scour depth dsNB without bedform (i.e. denoted as NB). ▵ds is the subtraction of mean of maximum live-bed scour depths and dsNB. Results show that, for 2-D structures, the baseline scour depth is negligible (dsNB→0), while the live-bed scour is mainly caused by the approaching bedform. The dynamic scour amplification normalized by the approaching bedform height (▵ds/Hb) varies between 0.5∼2 depending on the upstream angle. Specifically, ▵ds/Hb decreases with the increase of upstream. For uniform 3-D structures, the local flow could cause a considerable baseline scour depth, and ▵ds/Hb varies between 0.25∼0.5 and decreases with an increase in the flow capacity to deform and damp the approaching bedforms. For complex 3-D structures (e.g. complex piers), the flow pressurisation beneath the structural components (e.g. pile-caps) could magnify ▵ds/Hb to near 1. Summarising experimental data shows that ▵ds/Hb is inversely correlated with ds_NB/y0, where y0 is flow depth. Finally, new equations are proposed for estimating the dynamic scour amplification at various instream structures with design rules recommended. This study, by the first time, enables the understanding of the time-sensitive scour amplification at multiple instream structures from a non-static perspective.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"3 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80090716","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. Aydin, A. Baylar, F. Ozkan, M. C. Tuna, Mualla Ozturk
Gated conduits involve high-velocity air-water flow. When the studies on the gated conduits are examined, it is determined that the air-demand ratio changed according to the hydraulic and geometric parameters. However, no study has investigated the effect of the cross-sectional geometry of high-head conduits with a sluice gate on the air-demand ratio. In this study, the effect of conduit cross-sectional geometry on the air-demand ratio is examined. Results indicate that conduit cross-sectional geometry is an important effect on the air-demand ratio, especially at 10% and 15% gate opening rates. It is seen that the effect of the conduit geometry on the air-demand ratio decreases at 20%, and greater gate opening rates. Moreover, a formula for the air-demand ratio is presented relating the air-demand ratio to the gate opening rate, Froude number, hydraulic radius, and conduit length was presented for estimating the air-demand ratio.
{"title":"An experimental investigation of the geometry effect on air-demand ratio in conduits with a sluice gate","authors":"A. Aydin, A. Baylar, F. Ozkan, M. C. Tuna, Mualla Ozturk","doi":"10.1680/jwama.22.00048","DOIUrl":"https://doi.org/10.1680/jwama.22.00048","url":null,"abstract":"Gated conduits involve high-velocity air-water flow. When the studies on the gated conduits are examined, it is determined that the air-demand ratio changed according to the hydraulic and geometric parameters. However, no study has investigated the effect of the cross-sectional geometry of high-head conduits with a sluice gate on the air-demand ratio. In this study, the effect of conduit cross-sectional geometry on the air-demand ratio is examined. Results indicate that conduit cross-sectional geometry is an important effect on the air-demand ratio, especially at 10% and 15% gate opening rates. It is seen that the effect of the conduit geometry on the air-demand ratio decreases at 20%, and greater gate opening rates. Moreover, a formula for the air-demand ratio is presented relating the air-demand ratio to the gate opening rate, Froude number, hydraulic radius, and conduit length was presented for estimating the air-demand ratio.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"13 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73500333","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}
Diversion head works, also called weirs or barrages, are structures constructed across rivers or canals to store water or raise water level. The design of diversion weir structures involves calculating the depth, length and thickness parameters of the horizontal and sloping aprons and sheet pile cut-offs. The design parameters of a diversion weir structure, which have complex non-linear relationships, are determined traditionally using empirically derived recommendations and iterations to achieve structural stability against failures due to scour, uplift, sliding, piping and overturning. However, current design approaches do not explicitly explore the trade-offs between the many relevant design objectives; failing to reveal possibly superior designs. This article proposes a multi-objective optimization design approach for a diversion weir structure. The article also provides a free and open-source code that can be used as a design tool. The method is demonstrated on a stylised design problem. The results show the method reveals solutions with diverse balances of stability metrics and cost; with the optimal relationship of parameter values of components also varying based on the relative cost of sheet pile and apron construction materials. Key Points 1. Current design approaches for diversion structures on permeable media do not explore the trade-offs between the many relevant design objectives, failing to reveal possibly superior designs 2. A design formulation for multi-objective optimization of diversion weir structures is proposed. 3. Multi objective optimization achieves substantial improvement in stability of the structure and cost.
{"title":"Optimised multi-objective design of weir structures","authors":"R. Geressu, T. Tarekegn, E. Demissie","doi":"10.1680/jwama.22.00002","DOIUrl":"https://doi.org/10.1680/jwama.22.00002","url":null,"abstract":"Diversion head works, also called weirs or barrages, are structures constructed across rivers or canals to store water or raise water level. The design of diversion weir structures involves calculating the depth, length and thickness parameters of the horizontal and sloping aprons and sheet pile cut-offs. The design parameters of a diversion weir structure, which have complex non-linear relationships, are determined traditionally using empirically derived recommendations and iterations to achieve structural stability against failures due to scour, uplift, sliding, piping and overturning. However, current design approaches do not explicitly explore the trade-offs between the many relevant design objectives; failing to reveal possibly superior designs. This article proposes a multi-objective optimization design approach for a diversion weir structure. The article also provides a free and open-source code that can be used as a design tool. The method is demonstrated on a stylised design problem. The results show the method reveals solutions with diverse balances of stability metrics and cost; with the optimal relationship of parameter values of components also varying based on the relative cost of sheet pile and apron construction materials. Key Points 1. Current design approaches for diversion structures on permeable media do not explore the trade-offs between the many relevant design objectives, failing to reveal possibly superior designs 2. A design formulation for multi-objective optimization of diversion weir structures is proposed. 3. Multi objective optimization achieves substantial improvement in stability of the structure and cost.","PeriodicalId":54569,"journal":{"name":"Proceedings of the Institution of Civil Engineers-Water Management","volume":"516 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77117636","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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