scholarly journals Scouring of Replenished Sediment through Reservoir Flood Discharge Affects Suspended Sediment Concentrations at Downstream River Water Intake

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1998 ◽  
Author(s):  
Lee ◽  
Lai ◽  
Guo ◽  
Sumi
Keyword(s):  
Physical Model ◽  
Water Intake ◽  
Dry Density ◽  
Dredged Sediment ◽  
Flood Duration ◽  
Flood Discharge ◽  
Regression Relationship ◽  
Suspended Sediment Concentrations ◽  
Shihmen Reservoir ◽  
Scouring Process

Dredging is a commonly used sedimentation management strategy to remove mechanically deposited sediment from reservoirs. However, dredged sediment disposal is costly. Dredged sediment can be considered a beneficial resource and used for riverbed replenishment to prevent downstream riverbed degradation and improve aquatic habitats. This study investigated the feasibility of using dredged deposits with cohesive sediment for replenishment at the Shihmen Reservoir. Using the criterion of critical scour velocity, we conducted hydraulic assessments and identified the feasible replenishment area as the experimental domain. A physical model was developed to mimic the scouring process in the replenishment area. By applying dynamic similarity for scouring fine replenished sediment, we derived the regression relationship between flow-critical velocity and sediment-dry density, and used it for model ratio scaling of the grain size, dry density, and concentration in the physical model. Scoured sediment concentrations were measured to study the scour ratio at various flood discharges. Experimental results indicated that the scour ratio was related to factors such as flood discharge, flood duration, and water content of the replenished sediment. The reduction ratio of the concentration of sediment scoured from the replenishment area to the concentration of sediment at the downstream water intake was approximately 90% in the present study.

scholarly journals Effects of Water Intake Layout along the Wharf Shoreline on Ships

2019 ◽  
Vol 26 (4) ◽  
pp. 165-171
Author(s):  
Xian-wei Kong ◽  
Lei Ding ◽  
Hai-cheng Liu ◽  
Jing Qu ◽  
Xiao-song Li
Keyword(s):  
Numerical Model ◽  
Water Level ◽  
Physical Model ◽  
Water Intake ◽  
Hydrodynamic Forces ◽  
Lateral Flow ◽  
Real Situation ◽  
The Real ◽  
Level Difference ◽  
Two Sides

Abstract The construction of a water intake along the wharf shoreline can realise the intensive and comprehensive utilisation of the shoreline. However, since the water intake will increase the lateral flow at the wharf and also the hydrodynamic forces on ships, it will bring risks to ships mooring and leaving. The effects of the water intake on ships are studied using a physical model, numerical model and standard formulas. The results show that it leads to an increase of the hydrodynamic forces acting on the ship when the standard formulas are used to calculate the forces without considering the water level difference between the two sides of the ship. The results of the physical model are closer to the real situation. Measures that can effectively reduce the influence of the water intake on ships are proposed by increasing the distance between the wharf front and the front of the water intake as well as the depth of the water inlet windows.

scholarly journals Increase fish protective efficiency constructions of meliorative water intake

2020 ◽  
pp. 69-73
Author(s):  
Svetlana Mikhailovna Dragunova ◽  
Yevgeniy Vladimirovich, Кuznetsov ◽  
Anna Yevgenievna Khadzhidi
Keyword(s):  
Physical Model ◽  
Water Intake ◽  
Flow Rate ◽  
Juvenile Fish ◽  
Protective Efficiency ◽  
Irrigation Systems ◽  
Relative Flow Rate ◽  
Reclamation System ◽  
Relative Flow ◽  
Fish Protection

The article solves the problem of increasing the level of protection of juvenile fish to a standard indicator by the modernization of individual elements of fish protection of ameliorative water intake of irrigation systems. The design of an integrated fish-protecting structure with a logging boom adapted to hydrology and the rhythm of migration of juvenile fish from irrigation sources has been proposed. The results of studies on a physical model, taking into account the costs of the reclamation system, show an increase in the efficiency of the combined fish protection structure with a harbor for reclamation water intakes in the range of 78,5–84,0 %, depending on the relative flow rate on the shelf of the sanctuary.

scholarly journals An Improved Empirical Model for Flood Discharge Atomization and Its Application to Optimize the Flip Bucket of the Nazixia Project

2019 ◽  
Vol 16 (3) ◽  
pp. 316 ◽  
Author(s):  
Jijian Lian ◽  
Junling He ◽  
Fang Liu ◽  
Danjie Ran ◽  
Xiaoqun Wang ◽  
...  
Keyword(s):  
Physical Model ◽  
Model Test ◽  
Empirical Model ◽  
Rainfall Intensity ◽  
Droplet Diameter ◽  
Heavy Rain ◽  
Physical Model Test ◽  
Rain Area ◽  
Left Wall ◽  
Flood Discharge

Flood discharge atomization is a serious challenge that threatens the daily lives of the residents around the dam area as well as the safety of the water conservancy project. This research aims to improve the prediction accuracy of the stochastic splash model. A physical model test with four types of flip bucket is conducted to obtain the hydraulic parameters of the impinging outer edge of the water jet, the relationship of the splashing droplet diameter with its corresponding velocity, and the spatial distribution of the downstream nappe wind. The factors mentioned above are introduced to formulate the empirical model. The rule obtained from the numerical analyses is compared with the results of the physical model test and the prototype observations, which yields a solid agreement. The numerical results indicate that the powerhouse is no longer in the heavy rain area when adopting the flip bucket whose curved surface is attached to the left wall. The rainfall intensity of the powerhouse is significantly weaker than that of other types under the designed condition, so we choose it as the recommended bucket type. Meanwhile, we compare the rainfall intensity distribution of the original bucket and the recommended bucket under different discharge which rates ranging from 150.71 to 1094.9 m3/s. It is found that the powerhouse and the owner camp are no longer in the heavy rain area under all of the working conditions. Finally, it is shown that the atomization influence during the flood discharge can be reduced by using the recommended bucket.

scholarly journals May a Standard VOF Numerical Simulation Adequately Complete Spillway Laboratory Measurements in an Operational Context? The Case of Sa Stria Dam

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1606
Author(s):  
Maria Grazia Badas ◽  
Riccardo Rossi ◽  
Michela Garau
Keyword(s):  
Numerical Simulation ◽  
Physical Model ◽  
Numerical Models ◽  
Relevant Information ◽  
Mitigation Measures ◽  
Laboratory Measurements ◽  
Concrete Gravity Dam ◽  
Flood Discharge ◽  
Vof Model ◽  
Under Construction

The present work aims to assess whether a standard numerical simulation (RANS-VOF model with k − ϵ closure) can adequately model experimental measurements obtained in a dam physical model. The investigation is carried out on the Sa Stria Dam, a roller compacted concrete gravity dam currently under construction in Southern Sardinia (Italy). The original project, for which a physical model was simulated, included a downstream secondary dam. However, due to both economic and technical reasons, the secondary dam may not be built. Hence, it is important to assess the flood discharge routing and energy dissipation in the modified plan. Numerical validation is performed adopting the same laboratory configuration, in presence of the downstream dam, and results show a good agreement with mean experimental variables (i.e., pressure, water level). An alternative configuration without the downstream dam is here numerically tested to understand the conditions of flood discharge and assess whether its results can give relevant information for the design of mitigation measures. The topic is of interest also from a more general perspective. Indeed, the feasibility to integrate numerical models with existing laboratory measurements can be very useful not only for new constructions but also for existing dams, which may need either maintenance or upgrading works, such as in case of flood discharge increment.

scholarly journals Quantifying the contribution of flood intensity indicators with the projection pursuit model

2017 ◽  
Vol 49 (1) ◽  
pp. 60-71 ◽  
Author(s):  
Lina Wang ◽  
Yanqing Lian ◽  
Xiaohong Chen
Keyword(s):  
Southern China ◽  
Projection Pursuit ◽  
Flood Events ◽  
Flood Duration ◽  
Flood Discharge ◽  
Wujiang River ◽  
Flood Volume ◽  
Projection Pursuit Model ◽  
Flood Intensity ◽  
Peak Flood

Abstract Identifying the various factors that affect the intensity of a flood event, such as its duration and volume, is essential for strategic planning and flood management. Further, quantifying the impacts of these major factors on flood intensity using the contribution rate is essential, but technically challenging. In this study, the authors have adopted the projection pursuit model to quantify the contribution rates of peak flood stage and peak flood discharge, flood duration, and total flood volume (the maximum 12-, 24-, and 72-hour flood volumes) in the Wujiang River in Southern China. This study showed that peak flood discharge and total flood volume were the two dominant factors impacting flood intensity. Although flood duration can be a major factor for some flood events, it contributed the least to flood intensity for most of the historic flood events studied. Likewise, the maximum 24-hour and 72-hour flood volumes contributed little to flood intensity. Findings from this study not only demonstrated the successful adoption of the projection pursuit model for contribution rates, but also provided critical information for planning and managing the regional hydraulic resources in the Wujiang River.

Investigation of scours on a physical model of the Hričov weir using photogrammetry

2021 ◽  
Author(s):  
Martin Pavúček ◽  
Ján Rumann ◽  
Peter Dušička
Keyword(s):  
Flow Control ◽  
Physical Model ◽  
Short Range ◽  
Digital Models ◽  
Stilling Basin ◽  
Flood Discharge ◽  
Almost All ◽  
Contactless Measurements

Abstract Scours creation in riverbed at the Hričov weir is a permanent problem since its construction. It is caused by the shortened stilling basin of the weir. In almost all cases of flow control at the weir the energy is not dissipated sufficiently. A 3D physical model was built in the hydraulic laboratory to investigate the measures for reduction of the scour creation. To simulate uneven loads on the downstream riverbed, a flood discharge controlled by the weir in symmetric and asymmetric operations was used for simulations. The scours were evaluated using short-range photogrammetry for contactless measurements. Based on this method digital models of the riverbed for each simulation were created and the scours were assessed to determine the effect of the investigated measures on scour reduction.

State of a Bentonite Barrier after 8 Years of Heating and Hydration in the Laboratory

2006 ◽  
Vol 985 ◽  
Author(s):  
Maria Victoria Villar ◽  
Ana María Fernández ◽  
Roberto Gómez ◽  
José F. Barrenechea ◽  
F. Javier Luque ◽  
...  
Keyword(s):  
Laboratory Test ◽  
Specific Surface ◽  
Water Content ◽  
Surface Area ◽  
Specific Surface Area ◽  
Water Intake ◽  
Bottom Surface ◽  
Dry Density ◽  
Total Length ◽  
Swelling Capacity

AbstractThe conditions of the bentonite in an engineered barrier for HLW disposal have been simulated in a laboratory test. Six cylindrical blocks of bentonite compacted at a dry density of 1.64 g/cm3 were piled up in a hermetic Teflon cell. The total length of clay inside the cell was 60 cm. The bottom surface of the bentonite was heated at 100°C while the top surface was injected with granitic water. The duration of the test was 7.6 years. The water intake was measured during the test and, at the end, the cell was dismounted and the dry density, water content, specific surface area, mineralogy, geochemistry and swelling capacity of the clay were measured in different sections along the blocks. The material used in this test is the FEBEX bentonite.

Physical Model Test of Water Intake Including Huge Pump Station and Drum Screen

2008 ◽  
Author(s):  
Sadegh Barzegar ◽  
Mohammad Banae ◽  
Mohammad Ali Hamed ◽  
Mohammad Qaheri Badr
Keyword(s):  
Physical Model ◽  
Water Intake ◽  
Reverse Flow ◽  
Flow Behavior ◽  
Cross Flow ◽  
Air Entrainment ◽  
Physical Model Test ◽  
Original Design ◽  
Low Velocity ◽  
Pump Station

A physical model, built at an undistorted scale of 1:15 tested the original design of the six drum screen and nineteen cooling water pump intake connected to header bay. The capacity of origin water intake including huge pump station and drum screen is 400,000 m3/hr. The study objectives were to evaluate as-designed screen bay and pump bay performance and to propose design modifications to optimize intake flow conditions with respect to head-losses, uniformity of the approach flow, evenness of pump throat velocity distribution, and free and subsurface vortex formation. The model was built and operated in accordance with froude-number similitude. It allowed accurate representation of complex flow patterns caused by the physical geometry of the approach bay and pump bays. The major factors that can affect the selection of a concept and design development for a water intake are: a) The occurrence of dead water zones, flow separation or reverse flow b) Vortex building and air entrainment in the pump compartments c) Submerged vortices building in the pump compartments d) Low velocity area e) Strong rotational flow f) Strong cross flow appear in front of pump units g) Pre rotation in the pump suction lines. Dye injection was used to examine the stratified flow behavior along water. The existing design of the pump bays was found to produce a uniform, symmetrical flow distribution in the approach flow, weak but persistent floor and side-wall-attached submerged vortices, avoiding cross flow and reverse flow in front of the pumps and negligible swirling motion in the pump suction. Modified design includes (i) profiling low velocity area (ii) adding flow deflectors along inner walls (iii) infill area of low velocity (iv) adding suspended baffle in front of drum screens (v) adding diffuser block in front of pumps (vi) provision of floating booms in front of pumps.

scholarly journals Generation of artificial transverse circulation in an open channel flow by submerged vanes

Vestnik MGSU ◽  
2019 ◽  
pp. 1158-1166 ◽  
Author(s):  
Alexey V. Klovsky ◽  
Dmitry V. Kozlov
Keyword(s):  
Physical Model ◽  
Multiple Regression ◽  
Water Intake ◽  
Theoretical Calculations ◽  
Physical Modelling ◽  
High Water ◽  
Operating Conditions ◽  
Multiple Regression Equation ◽  
Geometric Characteristics ◽  
Transverse Circulation

Abstract Introduction. In this article, we describe a method for sediment control in damless water intake hydraulic units consisting in artificial transverse circulation (ATC) generated by redistributing specific water flow rates in the cross-section of the supply channel. One of the simplest and most effective anti-sediment elements working according to this principle is the submerged vane (SV). The intensity of the ATC formed in the flow depends on the flow regime and the planned-geometric characteristics of the vanes. Available recommendations on the selection of the rational characteristics of SV under the conditions of river damless water intake appear to be contradictory, thus requiring clarification. This study is aimed at examining the interaction between SV and a model flow without water trapping under various planned-geometric characteristics of the vane and experimental hydraulic regimes of its work using a physical model of the errosion-resistant channel. In addition, we set out to assess the effect of essential parameters on the intensity of the ATC generated in the flow. Materials and methods. This research was based on physical modelling hydraulic studies and theoretical calculations. Five hydraulic modes of vane operation with different planned-geometric characteristics were studied using a physical model of the erosion-resistant channel. Multiple regression analysis of the obtained experimental data was carried out. Results. The results of laboratory hydraulic studies on the SV operating conditions are presented. Experimental dependencies characterising the intensity of the ATC generated in the flow are plotted. A multiple regression equation is derived for the amount of the data obtained. Conclusions. It is established that the relative height of the vane and its angle to the side of the flume (coastline) has a significant effect on the intensity of the generated ATC. It is experimentally confirmed for the first time that SV shows little efficiency in high water horizons in terms of in-flow ATC generation.

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