Control of sediment entry into an intake canal by using submerged vanes
08 Aug 2017-Vol. 1875, Iss: 1, pp 030007
TL;DR: In this paper, a rigid bed trapezoidal channel (side slopes, 1H: 1V) of bed width 15 cm, diverting at an angle of 45° from river model is used as an intake channel.
Abstract: River flow which is entering into an intake canal carries lot of sediment due to centrifugal action at river-intake junction and results in various problems. The present work aims to control sediment entry into an intake canal by modifying flow pattern using submerged vanes. Experiments are conducted in a 57.5 cm wide rectangular laboratory model filled with sediment, d50=0.28mm, for a constant discharge of 0.025m3/s and flow depth (H) of 8cm. A rigid bed trapezoidal channel (side slopes, 1H: 1V) of bed width 15 cm, diverting at an angle of 45° from river model is used as an intake channel. Submerged vanes of width 0.18H and 1mm thick are arranged in single and double rows at a spacing (Vs) of 8cm and 12cm. The angle of attack (θ) of vane with respect to flow direction in river model varies as 15°, 300 and 450. A total of seven vanes are arranged as a crest of wave with a central vane height of 0.625 H and decreasing gradually to 0.438H on either side. In single row vane arrangement, for ‘Vs’=8 cm and ‘θ’...
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TL;DR: In this study, the interest of Proper Orthogonal Decomposition (POD) for the construction of a statistical predictive model is demonstrated and a POD-PCE coupling methodology is presented, with particular focus on input data characteristics and training-set choice.
8 citations
Cites background from "Control of sediment entry into an i..."
...As a result, the carrying capacity of the water intake can be drastically reduced, by decreasing its effective area of transport [61]....
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Cites methods from "Control of sediment entry into an i..."
...Sruthi et al. (2017) used non-uniform height submerged vane arrangements to control sediment entry into an intake channel....
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TL;DR: In this article , three vanes were installed at a 20° angle maintaining for a water discharge ratio of q r ≈ 0.1 in a 90° water intake to study 3D flow patterns and sediment distribution.
Abstract: In this study, two experiments were conducted in a 90° water intake to study 3D flow patterns and sediment distribution using submerged vanes under sediment feeding and live-bed conditions. One column three vanes were installed at a 20° angle maintaining for a water discharge ratio of q r ≈ 0.1. Three-dimensional mean and turbulent velocity components of flow in a 90° channel intake were measured using acoustic Doppler velocimetry (ADV). Flow characteristics of the intake structure area with no vanes were compared with these conditions. Results showed that three vanes with a single column reduced the amount of sediment by 20% during intake diversion. In the downstream corner of the intake, high velocities were measured where scouring occurred. The vanes affected the intensity of secondary flow, turbulence energy, flow separation, and moved sediment deposition downstream of the main channel.
1 citations
01 Feb 2020
TL;DR: A review of the current state-of-the-art in hydrodynamics at asymmetric fluvial bifurcations can be found in this paper, where the authors identify the grey areas and gaps specifically in the investigation of complex turbulent behaviour of flow structures in open channels with lateral diversions.
Abstract: The supply of water for human consumption starts with the abstraction of ‘raw’ water from various sources. Most of these facilities convey raw water by pumping it directly from rivers via lateral channels to nearby water treatment plants, but this is badly affected by debris and sediment clogging at the intake structures. Lateral intakes are actually special cases
of river bifurcations, where the channel naturally divides into two different branches, each carrying part of the flow and sediment. Many researchers have completed studies on
bifurcations/diversions to understand the behaviour of water flow and sediment transport. However, a complete understanding of the phenomenon, especially in relation to secondary flows and vortices, is lacking up to this day. In fact, if this can be overcome, it will greatly contribute to the fundamental study of hydrodynamics at asymmetric fluvial bifurcations as well as in optimal design of diversions. Thus, the distribution of water flow in both main and lateral channels requires further detailed investigation. A review of the current state of research is discussed in this paper, with the objective of identifying the grey areas and gaps specifically in the investigation of complex turbulent behaviour of flow structures in open channels with lateral diversions.
1 citations
TL;DR: In this paper, the negative effect of sediment on hydraulic structures makes sustainability one of the most important things to consider in designing and operating of such structures. Intakes and pumping stations...
Abstract: The negative effect of sediment on hydraulic structures makes sustainability one of the most important things to consider in designing and operating of such structures. Intakes and pumping stations...
References
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TL;DR: Lupker et al. as discussed by the authors used a Rouse-based method to integrate the chemical composition of river sediments to derive the annual flux and grain size distributions of the sediments.
Abstract: [1] The Ganga River is one of the main conveyors of sediments produced by Himalayan erosion Determining the flux of elements transported through the system is essential to understand the dynamics of the basin This is hampered by the chemical heterogeneity of sediments observed both in the water column and under variable hydrodynamic conditions Using Acoustic Doppler Current Profiler (ADCP) acquisitions with sediment depth profile sampling of the Ganga in Bangladesh we build a simple model to derive the annual flux and grain size distributions of the sediments The model shows that ca 390 (±30) Mt of sediments are transported on average each year through the Ganga at Haring Bridge (Bangladesh) Modeled average sediment grain size parameters D 50 and D 84 are 27 (±4) and 123 (±9) mm, respectively Grain size parameters are used to infer average chemical compositions of the sediments owing to a strong grain size chemical composition relation The integrated sediment flux is characterized by low Al/Si and Fe/Si ratios that are close to those inferred for the Himalayan crust This implies that only limited sequestration occurs in the Gangetic floodplain The stored sediment flux is estimated to ca 10% of the initial Himalayan sediment flux by geochemical mass balance The associated, globally averaged sedimentation rates in the floodplain are found to be ca 008 mm/yr and yield average Himalayan erosion rate of ca 09 mm/yr This study stresses the need to carefully address the average composition of river sediments before solving large‐scale geochemical budgets Citation: Lupker, M, C France‐Lanord, J Lave, J Bouchez, V Galy, F Metivier, J Gaillardet, B Lartiges, and J-L Mugnier (2011), A Rouse‐based method to integrate the chemical composition of river sediments: Application to the Ganga basin,
168 citations
TL;DR: Submerged vanes as mentioned in this paper are small flow-training structures (foils), designed to modify the near-bed flow pattern and redistribute flow and sediment transport within the channel cross section.
Abstract: Recent research results with the submerged‐vane technique for sediment control in rivers are described. Submerged vanes are small flow‐training structures (foils), designed to modify the near‐bed flow pattern and redistribute flow and sediment transport within the channel cross section. The structures are installed at an angle of attack of 15–25° with the flow, and their initial height is 0.2–0.4 times local water depth at design stage. The vanes function by generating secondary circulation in the flow. The circulation alters magnitude and direction of the bed shear stresses and causes a change in the distributions of velocity, depth, and sediment transport in the area affected by the vanes. As a result, the river bed aggrades in one portion of the channel cross section and degrades in another. The vanes can be laid out to develop and maintain any desired bed topography. Vanes have been used successfully for protection of stream banks against erosion and for amelioration of shoaling problems at water inta...
139 citations
TL;DR: In this article, it was shown that short, vertical, submerged vanes installed at incidence to the channel axis in the outer half of a river-bend channel significantly reduce the secondary currents and the attendant undermining and high-velocity attack of the outer bank.
Abstract: It is shown, theoretically and by a physical model, that short, vertical, submerged vanes installed at incidence to the channel axis in the outer half of a river-bend channel significantly reduce the secondary currents and the attendant undermining and high-velocity attack of the outer bank. The effect of the vanes on the secondary flow is estimated by a simple torque calculation using the Kutta-Joukowski theorem. A design relation for the vane spacing is derived by equating the torque, about the channel centroid, produced by the flow curvature to that resulting from the lateral force exerted on the vanes. The relation is verified in an idealized, physical model of a bend of the Sacramento River, California.
133 citations
TL;DR: In this paper, the authors describe the design, installation and performance of a system of submerged vanes for erosion protection in a bend of the East Nishnabotna River, Iowa.
Abstract: A summary is given of the design, installation and performance of a system of submerged vanes (“Iowa Vanes”) for erosion protection in a bend of East Nishnabotna River, Iowa. The system functions by eliminating, or reducing, the centrifugally induced helical motion of the flow (the root cause of bank undermining). The system was installed during the summer of 1985. Its performance was evaluated with data obtained in surveys in the spring of 1986. The system was found to effectively reduce velocity and scour along the bank without changing the energy slope of the channel. Areas of design improvements were identified. The summary includes a brief description of the theoretical and experimental background for the design.
109 citations
TL;DR: The theory of submerged vanes described in the companion paper is tested with laboratory and field data as mentioned in this paper, and they suggest that the vane technique is a viable alternative to traditional techniques.
Abstract: The theory of submerged vanes described in the companion paper is tested with laboratory and field data. The laboratory data are from experiments in curved, and straight, recirculating sediment flumes. The field data are from river bends in which, prior to installation of vanes, the banks were eroding, and from a straightened bridge waterway in which sediment deposits were causing a change of channel alignment, bank erosion, and undermining of the bridge abutment. All data support the theory, and they suggest that the vane technique is a viable alternative to traditional techniques. The design procedure is described and illustrated with numerical examples, and vane material and typical vane layouts are discussed. Layouts are presented for protection of stream banks against erosion and for amelioration of shoaling problems in navigation channels, at water intakes, in bridge crossings, at river confluences, and at diversions.
103 citations