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Copyright of Water Conservancy Science & Techonlogy & Economy is the property of Water Conservancy Science & Technology & Economy Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to explore the performance and applicability of the flow metering flume in rectangular channels, the hydraulic performance tests were carried out by constructing the flow metering flume with different shrinkage ratios with Nystrom drip line. By analyzing the water depth of upstream and the critical water depth of throat section, the flow measurement formula of measuring flume was established, and the measuring characteristics of measuring flume, such as measuring accuracy, upstream Froude number, backwater height and head loss were discussed. The results show that the water depth in front of the measuring tank has a high correlation with the discharge, and the average error of measuring flow is 1.74%, which has a high measuring accuracy. The hydraulic factors of upstream Froude number, backwater height and head loss are all affected by the shrinkage ratio of water tank and overflow. Under the test conditions, the upstream Froude number is smaller than 0.4, the water flow is gentle, the height of backwater and head loss are small, and they all decrease with the increase of the shrinkage ratio of the water tank, and increase with the increase of the channel overflow. [ABSTRACT FROM AUTHOR]

When fish swim upstream in the long-distance fishways, fatigue may occur, thereby affecting their passage efficiency and passage time. Therefore, constructing suitable resting pools within the fishway is essential. In this study, a diversion pile was introduced into the resting pool of the vertical solt fishway while altering its installation position. A three-dimensional re-normalization group k–ε turbulent mathematical model was then employed to analyze how the diversion pile with distinct positions affects the hydraulic characteristics in the resting pool under different slope conditions. The results show that with the diversion pile at the two-thirds position of the partition wall's sidewall in the resting pool, the mainstream is effectively regulated to the central position, accompanied by a small degree of meandering. Under such an arrangement, although the diversion pile has an impact on the turbulent kinetic energy in the resting pool across various slope conditions, the influence is insignificant. Therefore, it is recommended to install the diversion pile at the two-thirds position of the partition wall's sidewall in the resting pool, which can adjust the hydraulic characteristics of the resting pool and provide a large range of low-velocity areas for fish to rest, thereby facilitating the passage efficiency. [ABSTRACT FROM AUTHOR]

Spillway is a hydraulic structure designed to release of excess water, from the upstream to the downstream area of a dam. In the present study, a three-dimensional numerical model was employed using Flow-3D software. The accuracy of the model was verified through experimentation with a physical model scaled at 1:77. The objective was to analyze the flow characteristics of a distinctive type of morning glory spillway (MGS) in the Dokan Dam in Iraq. The study investigated various flow characteristics, including the discharge release, pressure and velocity distributions, and Froude number characteristics. The findings revealed that the relative error of flow rates was generally under 5%, indicating a good agreement between the numerical and physical models. Also, the discharge fluctuation was observed at low water levels and disappeared at higher water levels, due to continuous discharge at elevated water levels. Regarding pressure distribution, most discrepancies between the physical and numerical results were concentrated at specific points within the vertical shaft, and the highest pressure recorded at the bottom of the vertical shaft. Furthermore, the maximum and minimum recorded average velocities were 26.78 and 0.78 m/s, observed at Sects. 3 and 4 for water levels of 516 and 512 m, respectively. Finally, the analysis of Froude numbers showed that the downstream tunnel's flow regime transitioned from subcritical (Fr < 1) for lower water levels (512 and 513 m) to supercritical (Fr > 1) for higher water levels (514, 515, and 516 m) due to increased flow velocities. [ABSTRACT FROM AUTHOR]

The commercial CFD package Fluent and the Reynolds stress model were used to simulate the hydraulic characteristics with three types of vegetation distribution: longitudinal, interlaced and patch. Each type was aggregated to the middle line l of the water flow in an equal proportion of 0.5, resulting in a total of nine landscape vegetation arrangements. The numerical model was verified and showed a high level of consistency with the experimental comparison; the results indicate the following: (1) As the distribution of landscape vegetation on both sides becomes increasingly concentrated from a loose state to the middle line l of the flow, the flow velocity declines and the maximum Reynolds stress rises, and the greater the Reynolds stress, the more powerful the shear layer, contributing to turbulence, generating mass and momentum exchange and enhancing the vertical transport of momentum. (2) Compared with the gap area, the flow velocity in the vegetation area is smaller, the turbulent kinetic energy is larger and the maximum Reynolds stress of the bottom flow is larger; the larger sediment particles tend to deposit in the gap area, while smaller sediments tend to deposit in the vegetation area. At the same time, the vegetation area is more prone to deposits than the gap area. (3) Under the same vegetation density, whether in the test area or the wake area, the water blocking capacity and the deposition capacity are in the following order: patch distribution pattern > interlaced distribution pattern > longitudinal distribution pattern. [ABSTRACT FROM AUTHOR]

The enormous energy carried by discharged water poses a serious threat to the Piano Key Weir (PKW) and its downstream hydraulic structures. However, previous research on energy dissipation in PKWs has mainly focused downstream effects, and the research methods have been largely limited to physical model experiments. To deeply investigate the discharge capacity and hydraulic characteristics of PKW, this study established a PKW model with universally applicable geometric parameters. By combining physical model experiments and numerical simulations, the flow pattern of the PKW, the discharge at the overflow edges, and the variation in the energy dissipation were revealed for different water heads. The results showed that the discharge of the side wall constitutes the majority of the total discharge at low water heads, resulting in a relatively high overall discharge efficiency. As the water head increases, the proportion of discharge from the inlet and outlet keys increases, while the proportion from the side wall decreases. This change results in less discharge from the side wall and a consequent reduction in the overall discharge efficiency. The PKW exhibits superior energy dissipation efficiency under low water heads. However, this efficiency exhibits an inverse relationship with an increasing water head. The overall energy dissipation efficiency can reach 40% to 70%. Additionally, the collision of the water flows inside the outlet chamber and the mixing of the overflow jet play a primary role in energy dissipation. The findings of this study have significant implications for hydraulic engineering construction and PKW operational safety. [ABSTRACT FROM AUTHOR]

Electrical submersible pump (ESP) is extensively utilized in industrial sectors such as petroleum, chemical, and nuclear energy. However, ESPs experience pressurization deterioration due to the high gas volume fraction (GVF), resulting in the pressurization failure. In this paper, a three-stage mixed-flow ESP with closed impeller structure is detailed analysis. The interstage hydraulic characteristics and pressurization deterioration mechanism of the mixed-flow ESP are investigated at various rotational speeds and inlet conditions by combining experimental and simulation. The population balance model (PBM) and renormalization group (RNG) κ-ε model are employed. As the liquid flowrate increases, the ESP experiences a "three-stage" downward trend in pressurization. It is discovered that the first booster stage has a lower inflow velocity and flow separation degree compared to the subsequent booster stages, resulting in a greater liquid-phase pressurization capacity. The gas-liquid pressurization exhibits a wave-shaped downward trend due to significant deterioration in stage-wise pressurization when the liquid flowrate is low. Once the inlet gas volume fraction (IGVF) reaches the first critical GVF, the gas aggregates on the impeller's suction surface are removed at the impeller outlet, creating an annular air mass, which creates a chaotic vortex absorbing the fluids' kinetic energy. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the increasing frequency of extreme weather events, heavy rainfall and flooding pose significant pressure on the flood discharge systems of tailings dams. Simple discharge systems are insufficient to meet the flood discharge requirements of tailings dams, while complex discharge systems, with their greater flood discharge capacity, are gradually being promoted. Although complex discharge systems can increase the flood discharge capacity of tailings dams, the flow patterns within the discharge systems become more complex. As a new type of discharge system layout, existing research lacks systematic analysis, and its complex flow characteristics are not clear. This paper relies on the flood discharge system of a large tailings dam to carry out theoretical calculations and derivations of the hydraulic characteristics of the complex flood discharge system. Hydraulic characteristics are observed through hydraulic model tests and verified using numerical simulations. Based on these three methods, a basis for further research on the hydraulic characteristics of complex flood discharge systems is provided. The main results are as follows: (1) The formulas for calculating the discharge flow rate Q under different flow states in the tailings dam design manual are not applicable to complex discharge systems; (2) Formulas for calculating the discharge flow rate Q under different flow states in complex discharge systems are proposed; by comparing model test values and numerical simulation values, the accuracy of the formulas for calculating the discharge flow rate Q in complex discharge systems is verified; (3) If the traditional mode is used to calculate the discharge flow rate Q in complex discharge systems, it is recommended to take the reduction coefficient as 0.55–0.56, and the model test values should also be referred to during flow state transitions.

This study aims to investigate sediment dynamics and scouring processes in the Shatt Al-Hilla reach of the Euphrates River, with a focus on the hydraulic characteristics and soil properties influencing meandering behavior and erosion susceptibility. Bed material samples were collected from 20 river sections to assess sediment characteristics. Laboratory analyses included specific gravity measurements, grain size distribution, and soil classification using the Unified Soil Classification System (USCS). Specific gravity values ranged from 2.61 to 2.77, and grain size analysis revealed d50 values between 0.166 mm and 0.339 mm. Soil classification identified a range of poorly graded sands (SP) and well-graded sands with silt (SW-SM). The study finds significant variability in sediment characteristics across the river sections. Sections with higher specific gravity and well-graded sediments show greater stability, while those with lower specific gravity and poorly graded sands are more prone to erosion and scouring. This variability affects bed stability and sediment transport dynamics. The results highlight that sediment composition and gradation play critical roles in scouring processes and riverbank stability. The study is limited to the specific reach of the Euphrates River and may not be generalizable to other river systems without similar sediment analyses. The findings emphasize the need for detailed sediment characterization in river management but do not address the long-term impacts of sediment dynamics on river morphology. Understanding sediment variability and its impact on scouring processes can aid in predicting erosion patterns and designing more effective river management practices tailored to specific sediment characteristics. This research provides novel insights into the relationship between sediment properties and scouring behavior in the Al-Hilla reach, filling gaps in the understanding of sediment dynamics in meandering rivers. The detailed analysis of sediment characteristics and their influence on river stability offers new perspectives for future research and practical applications in river management. [ABSTRACT FROM AUTHOR]

In order to explore the water characteristics of soil in reclaimed coal mines in semi-arid areas and make better use of the land in reclaimed mining areas, the basic physical properties, water characteristic curves, unsaturated water conductivity and water diffusion rate of the reclaimed mining areas were selected for four types of land use after the four land use modes of reclaimed mining areas: farmland, grassland, forest land and bare land. The results showed that the soil in the reclaimed mining area was sandy soil, with the highest porosity and water content of forest land, the lowest bulk density and clay content, the highest organic matter content in cultivated land and the lowest organic matter content in bare land. The content of sand grain in bare land is relatively high, and the powder content of cultivated land, grassland and forest land is relatively high, indicating that the mechanical composition of soil in mining area can be improved by three land use methods: returning land, grassland and forest. The Van-Genuchten (V-G) model could fit the soil moisture characteristic curve in the mining area well, the coefficient of determination R2 was greater than 0.99, the gravity water of the soil capillary decreased significantly with the increase of water suction, and the water holding capacity in the suction section before 2.5 kPa was shown as cultivated land > grassland > bare land > forest land, and with the increase of suction, the water holding capacity of forest land was better than that of other land types. The water release process mainly appeared in the 0−4.8 kPa suction section, and the cultivated land had the best water release capacity and the worst forest land. Soil porosity and unsaturated water conductivity were significantly positively correlated, and the soil structure of four types of unsaturated water conductivity was the best in forest land > bare land > arable land > grassland. The soil volume moisture content and water diffusion rate conformed to the empirical formula of D(θ)=Aexp(Bθ) and changed exponentially, and the water diffusivity D(θ) increased exponentially with the soil volume moisture content θ, and R2 was greater than 0.92, and the potential water transport capacity of forest land was the best, and the water diffusion rate of bare land changed the fastest with moisture content. The research results provide theoretical and data support for land use and ecological restoration of reclaimed coal mines in semi-arid areas.

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

One or two inner teeth were added to the bidirectional flow channel emitter to form four kinds of single inner tooth bidirectional flow channel emitters with different relative positions of inner teeth and four kinds of double inner tooth bidirectional flow channel emitters with different relative positions of inner teeth, so as to explore the advantages and disadvantages of the hydraulic performance of the bidirectional flow channel emitters before and after the addition of inner teeth. For each emitter, the three-dimensional modeling of the flow channel of the emitter was carried out by AutoCAD, and the flow state of the fluid inside the flow channel was simulated by Ansys Fluent. The local loss coefficient of the flow channel was calculated, and the flow coefficient and flow index were obtained by regression analysis. The results show that the local loss coefficient of the improved bidirectional flow channel is 11. 24-56. 89, which is significantly higher than that of the original bidirectional flow channel. The flow coefficient of the improved bidirectional flow channel is smaller than that of the original bidirectional flow channel. When the single inner tooth is located at the inlet of the branch channel, the flow index is the best, which is 5. 6% lower than that of the original bidirectional flow channel. The position of the inner tooth can affect the bidirectional flow ratio, which in turn affects the hydraulic performance, and verifies the internal relationship between the different flow ratios of the main and branch channels and the hydraulic performance. The research can provide reference for the structural optimization and hydraulic performance improvement of the bidirectional flow channel emitter [ABSTRACT FROM AUTHOR]

In recent times, drilling groundwater wells for irrigation, domestic, and industrial uses is increasing at a high rate in Saudi Arabia, meaning that groundwater is becoming a primary water resource. In the study region, over-exploitation and unsustainable performance severely deteriorate groundwater. Therefore, it is important to monitor the groundwater levels and quality as well as to detect the hydraulic parameters in order to plan and maintain groundwater sustainability. Knowledge of aquifer hydraulic parameters and groundwater quality is essential for the productivity planning of an aquifer. Therefore, this study carried out a thorough analysis on measured depth to groundwater data (2017 and 2022), borehole pumping test records, and chemical analysis of the collected water samples, especially in the presence of overexploitation and scarcity of recharge scale. To accomplish this aim, measurements of 113 groundwater wells (including 103 water samples) and analysis of 29 pumping tests between step and long-duration tests were made of all aquifer characteristics. These parameters consist of well loss, formation loss, well efficiency, specific capacity, transmissivity, hydraulic conductivity, resulted drawdown, and physiochemical parameters. Thematic maps were generated for all parameters using the geographic information system (GIS) and diagrams to strategize the groundwater productivity in Al-Madinah Al-Munawarah Province. The estimated hydraulic parameters are highly variable. Four distinct portions were identified for aquifer potentiality based on these varying ranges. Both the north and east of the region are good for groundwater productivity due to good aquifer materials, whereas the southwestern and western portions have relatively poor values. The analyzed groundwater was categorized as fresh to slightly salty water, with two primary chemical types identified showing a prevalence of mixed NaCl and Ca-Mg-SO4/Cl water. Finally, groundwater productivity assessment predicts that the aquifers can support the Al-Madinah Al-Munawarah Province demand for several years if certain well distributions are adopted and for a few hours/day of pumping rate. The maps that have been created can be examined to aid in making decisions related to hydrology. [ABSTRACT FROM AUTHOR]

Research shows that the novel vertical-slot, double-pool fishway can reduce the flow velocity at the vertical slots of the fishway, enhance the efficiency of the water flow in the chambers, and increase the fish passage area and migratory corridor for fish. Utilizing Fluent, two-dimensional and three-dimensional models of the novel fishway were established, and numerical simulation analysis was conducted on their hydraulic characteristics. The results indicate that the flow velocity at the cross-section of the middle vertical slot in the fishway pool decreases horizontally from left to right and increases vertically from top to bottom, with similar water flow distribution patterns on different vertical lines. The flow conditions and hydraulic characteristics of the surface, middle, and bottom layers in the pool are similar, mainly characterized by planar, two-dimensional flow. The error between the trajectory of the water flow in the main flow area and the maximum velocity value is within 10%. The novel vertical-slot, double-pool fishway retains the planar binary characteristics of traditional vertical-slot fishways. The results of the two-dimensional numerical simulation can be analogized to the vertical uniformization of the three-dimensional numerical simulation, providing support for the study of its two-dimensional numerical simulation of hydraulic characteristics and presenting a theoretical basis for the structural design and construction of fishways. [ABSTRACT FROM AUTHOR]

AbstractBottom protection (BP) is a commonly used engineering measure in river training. A 3D hydrodynamic numerical model is established to study the influence of the overall arrangements of BP structures on the hydraulic characteristics of the sharp bends. Under the action of the BP structures group, the maximum longitudinal flow velocity is closer to the water surface vertically and closer to the concave bank laterally compared with no BP. The high shear stress zones on the riverbed at the exit straight section of the bend do not occur. The so-called primary circulation after the apex of the bend gradually weakens and disappears. If the coverage rate of BP is increased to 1.5 times that of the sequential BP, the average longitudinal flow velocity near the bottom of BP decreases by 10% and the average bed shear stress at the outlet section of the bend decreases by 35%. In the staggered BP condition, the average bed shear stress at the outlet section of the bend is reduced by 23% compared with the sequential BP. Moreover, the results show that the protection effects of the dense BP and the staggered BP are better than that of sequential BP. [ABSTRACT FROM AUTHOR]

Restricted by the inlet and outlet position of the fishway, engineering geology, hub layout and other factors, the fishway project needs to arrange the turning section of the pool chamber at different angles to adapt to complex and ever-changing engineering environments. This article adopts numerical simulation method to study the flow field distribution law of the turning section of a fish lane with vertical slits on the same side at different turning angles α (90°≤α≤180°), and systematic optimization measures are proposed for different turning angles. The results show that when the turning angle α is greater than 90 °, the mainstream impacts the outer wall, and there is a large-scale recirculation zone in the middle of the pool. With the increase of the turning angle α, the impact of the mainstream is intensified, and the scale of the recirculation zone is further expanded. In view of the above flow field problems, the measures of adding rectifier guide plate are adopted for optimization. It is proposed that when the turning angle α is between 90° and 140°, the α0/α value of the guide plate position with better rectification increases from 1/4.0 to 1/2.8. When α is between 140° and 180°, the α0/α value is basically stable between 1/2.8 and 1/3.0. That is to say, with the gradual increase of the turning angle α, the better α0/α value increases first and then tends to be stable, It can provide reference for the optimization design of similar arrangement fishway in turning section structure. [ABSTRACT FROM AUTHOR]

In the stilling pool of the spillway and flushing tunnel, there are often problems such as unstable fluctuation range of hydraulic jump and even overtopping the side wall. In order to obtain a good energy dissipation and erosion prevention effect of the stilling pool, the fluid movement during the flood discharge process of the spillway and flushing tunnel was studied through a combination of numerical simulation and physical model testing, which was beneficial for gaining hydraulic dynamics of the flow field and the downstream riverbed erosion conditions . The hydraulic characteristics of water flow under different stilling pool body shape optimization schemes were analyzed, and those schemes were verified by physical experiments. The results show that the flow pattern is more stable under adding a rectangular tailgate at the stilling pool, the water surface fluctuation is reduced. At the same time, the maximum decrease of inlet and outlet velocity in the stilling pool is 7.66 m/s. The pressure distribution is uniform, no negative pressure is generated, and the energy dissipation rate reaches 80.60%. After the addition of the rectangular tailgate, the riverbed scour pit range of the design and verification conditions are reduced by 12.20 m and 13.30 m compared with the original scheme, and it' s maximum scour pit depth are reduced by 0.48 m and 1.00 m compared with the original scheme, respectively. The decrease of the riverbed scour pit range and the maximum scour pit depth shows that the addition of rectangular tailgate has obvious protective effect on the downstream. The research shows that the stilling pool body shape optimization scheme can effectively improve its energy dissipation. The flow field distribution of the optimized stilling pool body shape is uniform, which have great protection on the downstream river bed. The research results can provide reference for diversion and flood discharge and sand flushing projects. [ABSTRACT FROM AUTHOR]

Due to the long duration and high cost of traditional pumping tests, the response of well water levels to seismic waves, earth tides, and barometric pressure provides a feasible method for determining continuous changes in aquifer hydraulic parameters. Aimed at the problem that the response phase shift of well BB water levels to tide M2 is greater than that of tide O1, this paper preferentially calculated the time series changes in S, Be, n, and BKu based on the response mechanism of well water levels to barometric pressure and earth tides with the help of the smooth moving method. Then, by using the mixed flow model, the variation in the transmissivity and leakage coefficient over time was simultaneously obtained, and the evolution process and characteristics of aquifer parameters near well BB caused by the Wenchuan earthquake are ultimately discussed. The calculation results are basically consistent with the previous pumping test, and have been verified and compared by using other scholars' methods. This solving process avoids problems such as excessive dependence on initial values, multiple solutions, and unstable tide O1, which has a promoting effect on the study of the impact of seismic activity on aquifer systems. [ABSTRACT FROM AUTHOR]

The article presents a comprehensive analysis of the hydraulic characteristics of ash suspensions, in particular the removal of ash from the Dnieper Hydroelectric Station. The importance of this research is justified by the relevance of understanding hydrodynamic processes in suspensions, which is crucial for the efficiency of mineral resource processing. The study focuses on the investigation of the physico-chemical properties of suspensions, which is fundamental for the development and optimization of technological processes. The main goal of the article is to determine the discrepancies between theoretical calculations and experimental data in the context of the hydraulic characteristics of ash suspensions. Focusing on this issue, the research aims to make an important contribution to the accuracy of prediction and calculation of the behavior of suspensions, which has important practical applications. The research methodology includes a series of experiments to measure various hydraulic parameters of the suspension, including suspension density, solid phase weight content, and porosity. The experiments are based on a detailed analysis of ash samples collected from the Dnieper Hydroelectric Station. It is established that theoretical formulas for determining hydraulic characteristics are well confirmed experimentally. The difference is due to the accuracy of measuring the density of the solid phase and errors in measuring weight and volume; it is sufficiently small and does not have a fundamental character. [ABSTRACT FROM AUTHOR]

: Here internal structures were added into the curved side wall and vertical seam, in order to improve the fish passage efficiency of fishways. Auxiliary fish passage devices were arranged on the inner wall and bottom plate of the fishway. Six layouts were also combined to explore the effect on the fish upstream behavior using simulation and model testing. The results showed that the success rates of upstream migration were 36.7%, 43.3%, and 73.3%, respectively, for the combinations of barriers in schemes 1, 2, and 3. Because scheme 1 was set as more barriers, the flow velocity in the mainstream decreased rapidly to cause the vortex-like flows, where the fish was unable to identify the upstream direction. There was the a low flow velocity in the downstream half of the mainstream, leading to difficultly ascending. A group of barriers was removed perpendicular to the direction of flow in scheme 2. The mainstream flow was connected from the top to the bottom, indicating the fish upstream migration. The sScheme 3 was equipped with the a central connection and only one group of barriers on the side wall. The highest success rate was achieved for fish upstream migration. The wide distribution of mainstream flow velocity and large flow velocity differentiation were provided more selective areas for fish with the different physical abilities, thus improving the fish upstream migration. There were the hindering and disturbing effects of circular columns on the flow in the tank chamber, indicating the variation in the mainstream flow path and flow velocity distribution. There was the an increase in the mainstream branches with the upstream flow velocity decreased. The test fish was easily fieasily found the correct path. The maximum mainstream flow velocity was greatly contributed to the better better-ascending fish. An optimal number of recirculation zones were was also maintained to ensure the rest for upstream fish. The combinations (schemes 4, 5, and 6) of straight circular columns were introduced in the scheme 3 to further improve the effect of fish upstream migration. The success rates were 56.7%, 73.3%, and 90.0%, respectively, for the upstream migration. The internal disturbance was significant in the area that composed of internal barriers in scheme 4, resulting in a narrower middle mainstream width and lower flow velocity than on both sides. There was the a low flow velocity in the tail of the tank chamber. There was no benefit to inducing fish upstream migration. In scheme 5, the width of the middle mainstream increased, while the flow velocity in on both sides decreased. The lower flow velocity and longer distribution distance in the higher flow velocity area were promoted the fish upstream migration, while reducing the swimming difficulty. There was the a cylindrical diameter with one-half of the inlet width of the tank chamber in scheme 6. The highest success rate was then achieved for the test fish upstream migration. The middle mainstream flow velocity increased in the tank chamber. The mainstream was much clearer to fill with internal barriers. There was the a diffusion from the middle mainstream to both sides. The width of mainstream distribution increased for the fish upstream migration. In the recommended solution, the fish swimming was roughly followed the mainstream upstream, providing the multiple mainstream flow paths for fish. The pass efficiency of fish was improved with the large discrimination of flow velocity, the reasonable attenuation of mainstream flow velocity, and the flow pattern with the fewer backflow zones. [ABSTRACT FROM AUTHOR]

Submersible tubular pumps are an ideal choice for pump stations that require high flow rates and low lift. These pumps combine the unique features of submersible motors with axial flow pump technology, making them highly efficient and cost-effective. They have found extensive applications in China's rapidly developing water conservancy industry. In this research, we focus on investigating the pressure pulsation characteristics of the internal bulb body in a specific pump station project in China. To conduct our analysis, we utilize a model of the submersible tubular pump and strategically position 18 monitoring points. These monitoring points cover various sections, including the impeller inlet and outlet, guide vane outlet, as well as the inlet, middle, and outlet sections of the bulb body segment. To calculate the unsteady flow of the system, we employ numerical simulation techniques. By combining the outcomes of model tests, we determine the pressure pulsation characteristics. The comparison of results reveals a remarkable similarity between the efficiency–head curves obtained from the numerical simulation and the model test. While the model test yields slightly higher head results, the numerical simulation indicates slightly higher efficiency values. This finding lends strong support to the reliability of numerical simulation results, which can provide valuable insights for the design and optimization of submersible tubular pumps. Overall, submersible tubular pumps demonstrate their suitability for pump stations with high flow rates and low lift requirements. The study of pressure pulsation characteristics within the bulb body contributes to a better understanding of their performance and facilitates their further application in the field of water conservancy engineering. [ABSTRACT FROM AUTHOR]

The action of freeze–thaw (F–T) cycles of claystone exerts a profound impact on the slope stability of open-pit mines in water-rich regions. Microstructural changes are observed as a crucial factor in determining the hydraulic characteristics and mechanical behaviors of claystone. The present work integrates a micro-X-ray computed tomography (Micro-CT) scanner, equipped with image processing and three-dimensional (3D) reconstruction capabilities, employed to observe the microstructure of claystone under varying numbers of F–T cycles (0, 10, 20, 30, and 50). Furthermore, seepage numerical simulations based on Micro-CT measurements are conducted to evaluate the hydraulic characteristics. Through meticulous microscopic observation and mechanical analysis, the damage mechanism induced by F–T cycles is revealed and the evolutionary characteristics are analyzed. The two-dimensional (2D) images of 3D reconstructed models unveil the gradual initiation propagation and coalescence of an intricate fissuring network in claystone during the F–T cycles. As the number of F–T cycles increases from 0 to 50, the 3D porosity exhibits exponential growth. Additionally, the influence of F–T cycles substantially enhances the connectivity of fissures. The seepage numerical simulations demonstrate that the evolutionary progression of fissures substantially augments the number of flow paths and enhances permeability. The increase in permeability follows an exponential trend, reflecting the distribution and evolution of fissures under F–T cycles. The impact on permeability arises from a combination of micromechanical properties and the microstructure of claystones. The present research tries to elucidate the microscopic evolution of fissures and their corresponding hydraulic properties in water-saturated claystone, offering significant insights for investigating the slope stability of open-pit mines in regions. [ABSTRACT FROM AUTHOR]

The influence of the choice of computational dependencies for determining the coefficient of hydraulic resistance of pipelines restored using polymer hoses is numerically investigated. The results of calculating the hydraulic resistance coefficient of restored pipelines were compared according to the formulas of Blasius, Nikuradse, Shifrinson, Altschul, Volgin, as well as according to the dependence for calculating the hydraulic resistance of pipelines made of polymer materials according to SP 399.1325800.2018 "External water supply and sewerage systems made of polymer materials." An assessment of the impact of these calculations on the throughput of pipelines has been carried out. [ABSTRACT FROM AUTHOR]

【Objective】 In view of the lack of integrated facilities for measuring and controlling flow of Doudou (agricultural) channel in irrigation area, an integrated quantity control building-Measurement and Control Integrated Water Distribution Farm Gate was designed to explore its performance on trapezoidal channel. 【Method】 Using the combination of agricultural gate control disc valve and circular pipe to form an integrated water distribution gate (hereinafter referred to as the water distribution gate), the hydraulic characteristics and flow formulas of the water distribution gate under different flow rates and different opening of the agricultural gate control disc valve are studied by model test. 【Result】 ①The flow formula of Water Distribution Farm Gate was fitted and designed. The average error of the flow calculated by the formula was 4.34% compared with the measured flow, and the measurement error of flow was less than ±5%, which met the water accuracy requirements of irrigation area. ②The “optimal water head” of Water Distribution Farm Gate is between 0.475 and 0.575 L in the overall length of the pipeline.③The water distribution gate mainly produces local head loss and head loss along the distance when the water flow passes through the disc valve, and the range of head loss is 29.54% to 38.89%. 【Conclusion】 When the flow rate is in the range of 30 - 65 m3/h, under different flow conditions and disc valve opening degree, the water metering can be carried out in the final channel of the irrigation area. Therefore, Water Distribution Farm Gate has a high prospect of popularization and practical application value in the future.

[Objective] Stressed by harsh environmental factors such as scarce precipitation and large evaporation, the desert Gobi is characterized as spare vegetation and severe soil and water losses. Therefore, exploring suitable soil improvement methods to improve soil water retention and water holding capacity is very important for the development of Gobi ecological agriculture. [Methods] The hydraulic-infiltration characteristics of the 3 groups of coconut coir-type ecological conservation substrates with better physicochemical properties (aeolian soil∶ coconut coir∶ organic fertilizer∶ artificial peat = 3.5∶3∶3∶1 or 3∶4∶3∶1 or 2∶5∶3∶1, i.e., T1, T2, T3) were tested compared to the control substrate with no coconut coir (aeolian soil∶ organic fertilizer∶ artificial peat = 7∶3∶1, T0). The relationship between matrix water and suction was determined by the centrifuge method, and then the hydraulic characteristics were explored. Then, the infiltration characteristics of the substrates were analyzed by the indoor infiltration test of the soil column with constant water head; and, based on the measured indicators, the proportion optimization was carried out by the coordinate comprehensive evaluation method. [Results] Compared with the T0 group, the field water retention capacity of the T1, T2 and T3 groups increased by 10.22%, 12.13% and 14.99%, and the total effective water content increased by 8.10%, 8.81% and 12.83%, respectively. In the stage of Pf=1.8~3.8 (logarithmic matrix suction), the average specific water capacity of each group showed a law of T3 > T2 > T1 > T0, and according to the gray correlation analysis (RGA) method, the infiltration capacity was ranked as T3 > T2 > T0 > T1. [Conclusion] The results showed that a suitable proportion of coconut coir mixing changes the effective water content and pore distribution ratio, which can significantly improve the water retention capacity of the substrate. From the perspective of physicochemical properties, hydraulic and infiltration characteristics, the T3 ratio is optimal.

This study investigated the hydraulic characteristics of stormwater sumps and their design optimization for sediment retention using physical experiments. Particle image velocimetry was utilized to measure the flow field, and the use of internal structures was investigated for improving solids retention. Results indicate that these internal structures can significantly improve the sediment removal efficiency of suspended solids with an average size of 125 μm, resulting in an efficiency improvement of 20–30%. Additionally, a modified Péclet number was proposed to more accurately evaluate the sediment removal efficiency of stormwater sumps, and recommendations were provided for further improving and optimizing sump design. This study provides insights into the hydraulic characteristics of stormwater sumps and has important implications for optimizing and designing particle removal systems for various industrial and environmental applications. HIGHLIGHTS The study demonstrates that incorporating enhancements leads to a substantial increase (20–30%) in the efficiency of removing suspended solids in stormwater sumps.; The study introduces a modified dimensionless number that provides a more precise evaluation of sediment removal efficiency in stormwater sumps.; The study highlights that scaling, with a ratio of up to 6, can reasonably predict particle removal efficiency.;

The commercial CFD package Fluent and the Reynolds stress model were used to simulate the hydraulic characteristics with three types of vegetation distribution: longitudinal, interlaced and patch. Each type was aggregated to the middle line l of the water flow in an equal proportion of 0.5, resulting in a total of nine landscape vegetation arrangements. The numerical model was verified and showed a high level of consistency with the experimental comparison; the results indicate the following: (1) As the distribution of landscape vegetation on both sides becomes increasingly concentrated from a loose state to the middle line l of the flow, the flow velocity declines and the maximum Reynolds stress rises, and the greater the Reynolds stress, the more powerful the shear layer, contributing to turbulence, generating mass and momentum exchange and enhancing the vertical transport of momentum. (2) Compared with the gap area, the flow velocity in the vegetation area is smaller, the turbulent kinetic energy is larger and the maximum Reynolds stress of the bottom flow is larger; the larger sediment particles tend to deposit in the gap area, while smaller sediments tend to deposit in the vegetation area. At the same time, the vegetation area is more prone to deposits than the gap area. (3) Under the same vegetation density, whether in the test area or the wake area, the water blocking capacity and the deposition capacity are in the following order: patch distribution pattern > interlaced distribution pattern > longitudinal distribution pattern.

The enormous energy carried by discharged water poses a serious threat to the Piano Key Weir (PKW) and its downstream hydraulic structures. However, previous research on energy dissipation in PKWs has mainly focused downstream effects, and the research methods have been largely limited to physical model experiments. To deeply investigate the discharge capacity and hydraulic characteristics of PKW, this study established a PKW model with universally applicable geometric parameters. By combining physical model experiments and numerical simulations, the flow pattern of the PKW, the discharge at the overflow edges, and the variation in the energy dissipation were revealed for different water heads. The results showed that the discharge of the side wall constitutes the majority of the total discharge at low water heads, resulting in a relatively high overall discharge efficiency. As the water head increases, the proportion of discharge from the inlet and outlet keys increases, while the proportion from the side wall decreases. This change results in less discharge from the side wall and a consequent reduction in the overall discharge efficiency. The PKW exhibits superior energy dissipation efficiency under low water heads. However, this efficiency exhibits an inverse relationship with an increasing water head. The overall energy dissipation efficiency can reach 40% to 70%. Additionally, the collision of the water flows inside the outlet chamber and the mixing of the overflow jet play a primary role in energy dissipation. The findings of this study have significant implications for hydraulic engineering construction and PKW operational safety.

Copyright of Bulletin of Soil & Water Conservation is the property of Bulletin of Soil & Water Conservation Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Hydraulic jetting is a form of fracturing that involves using a high-pressure jet of water to create fractures in the reservoir rock with a nozzle serving as the central component of the hydraulic sandblasting perforation tool. In this study, the flow behavior of the nozzle is simulated numerically in the framework of a SST k-ω turbulence model. The results show that the nozzle structure can significantly influence the jet performance and related cavitation effect. Through orthogonal experiments, the nozzle geometric parameters are optimized, and the following configuration is found accordingly: contraction angle 20°, contraction segment length 6 mm, cylindrical segment diameter 6 mm, cylindrical segment length 12 mm, spread segment length 10 mm, and spread angle 55°. [ABSTRACT FROM AUTHOR]

The hydraulic tunnel will have cracks, wear, falling blocks, scour holes and other defects during long years of operation, which will greatly affect the safety of the project. In view of the causes of scour holes in the lining bottom plate of hydraulic tunnel and their impact on the structural safety, numerical simulation of hydraulic characteristic parameters of tunnel section was carried out, the causes of scour holes in the lining bottom plate were analyzed from the hydraulic point of view, and the impact of different scour hole depths on the stress of the lining structure under operation and maintenance conditions was analyzed. Combined with monitoring data and simulation results, the bearing capacity of the section at the location of the scour hole was checked. The results show that the velocity and turbulent kinetic energy of the tunnel floor are both large, and the tunnel floor is most vulnerable to high-speed water erosion and damage during operation. After the scour hole is formed, it mainly affects the symmetry and numerical value of the bending moment of the tunnel bottom plate and side wall, and has little influence on the axial force and shear force. Due to the difference of internal and external water pressure control, compared with the maintenance condition, the impact of scour holes on the structural safety under the operating condition is more obvious. The scour holes lead to a significant reduction in the flexural rigidity of the section. With the increase of scour hole depth, the flexural bearing capacity gradually decreases. During the project operation, attention should be paid to the scour of the bottom plate concrete under the operating condition. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

【Objective】 The weir-flume apparatus, consisting of a measuring flume and a measuring weir, is an innovative device for monitoring and controlling open channel flow. Installed across channels, it can measure water flow, elevates upstream water level, and enhances ecological connectivity in rivers in diverse geographical conditions. While measurement formulas and hydraulic characteristics have been experimentally investigated for small flow with shallow water depth, there is a lack of study for large flow. This paper aims to bridge this gap by studying the vertical and longitudinal velocity profiles as well as spatial distribution of flow field under high flow conditions. 【Method】 The analysis was based on numerical modelling. The FLOW-3D software was used to simulate hydraulic performance of a weir-flume device under 17 flow rates ranging from 10.13 to 200 L/s. From the simulated results we analyzed the impact of flow rate on water depth, Froude number (Fr), and velocities within both the in-groove flow and the weir flow. 【Result】 As the flow rate increased, the Fr and velocity in the central longitudinal section of the device initially increased and then tapered off. The flow in the upstream of the device remained stable, with Fr ranging from 0.1 to 0.3 and velocities varying between 0.08 and 0.5 m/s. Both Fr and velocity gradually increased with the increase in flow rate. After entering the device, Fr and flow velocity exhibited a significant surge. A wide range of thin water layers emerged in the downstream of the device, with the maximum Fr and velocities being 3 to 4.6 and 1.05 to 2.06 m/s, respectively. A subdued water jump was observed downstream of the in-groove flow, while the downstream of the weir showed a jet stream with Fr>1. Additionally, diffused water generated a rhomboid wave at the side bank. We derived a formula from the numerical simulations; its maximum relative error was 6.11% for flow rate below 100 L/s, beyond which the relative error gradually increased. 【Conclusion】 The numerical results obtained from FLOW-3D agreed well with the test data, validating the accuracy and consistency of the derived formula for analyzing measurement data from the weir-flume device. This work bridges a critical knowledge gap, enabling more precise assessment and control of open channel flow under various conditions.

In recent times, drilling groundwater wells for irrigation, domestic, and industrial uses is increasing at a high rate in Saudi Arabia, meaning that groundwater is becoming a primary water resource. In the study region, over-exploitation and unsustainable performance severely deteriorate groundwater. Therefore, it is important to monitor the groundwater levels and quality as well as to detect the hydraulic parameters in order to plan and maintain groundwater sustainability. Knowledge of aquifer hydraulic parameters and groundwater quality is essential for the productivity planning of an aquifer. Therefore, this study carried out a thorough analysis on measured depth to groundwater data (2017 and 2022), borehole pumping test records, and chemical analysis of the collected water samples, especially in the presence of overexploitation and scarcity of recharge scale. To accomplish this aim, measurements of 113 groundwater wells (including 103 water samples) and analysis of 29 pumping tests between step and long-duration tests were made of all aquifer characteristics. These parameters consist of well loss, formation loss, well efficiency, specific capacity, transmissivity, hydraulic conductivity, resulted drawdown, and physiochemical parameters. Thematic maps were generated for all parameters using the geographic information system (GIS) and diagrams to strategize the groundwater productivity in Al-Madinah Al-Munawarah Province. The estimated hydraulic parameters are highly variable. Four distinct portions were identified for aquifer potentiality based on these varying ranges. Both the north and east of the region are good for groundwater productivity due to good aquifer materials, whereas the southwestern and western portions have relatively poor values. The analyzed groundwater was categorized as fresh to slightly salty water, with two primary chemical types identified showing a prevalence of mixed NaCl and Ca-Mg-SO4/Cl water. Finally, groundwater productivity assessment predicts that the aquifers can support the Al-Madinah Al-Munawarah Province demand for several years if certain well distributions are adopted and for a few hours/day of pumping rate. The maps that have been created can be examined to aid in making decisions related to hydrology.

Research shows that the novel vertical-slot, double-pool fishway can reduce the flow velocity at the vertical slots of the fishway, enhance the efficiency of the water flow in the chambers, and increase the fish passage area and migratory corridor for fish. Utilizing Fluent, two-dimensional and three-dimensional models of the novel fishway were established, and numerical simulation analysis was conducted on their hydraulic characteristics. The results indicate that the flow velocity at the cross-section of the middle vertical slot in the fishway pool decreases horizontally from left to right and increases vertically from top to bottom, with similar water flow distribution patterns on different vertical lines. The flow conditions and hydraulic characteristics of the surface, middle, and bottom layers in the pool are similar, mainly characterized by planar, two-dimensional flow. The error between the trajectory of the water flow in the main flow area and the maximum velocity value is within 10%. The novel vertical-slot, double-pool fishway retains the planar binary characteristics of traditional vertical-slot fishways. The results of the two-dimensional numerical simulation can be analogized to the vertical uniformization of the three-dimensional numerical simulation, providing support for the study of its two-dimensional numerical simulation of hydraulic characteristics and presenting a theoretical basis for the structural design and construction of fishways.

This paper focuses on a 1000 MW Francis turbine and conducts a numerical analysis of the entire flow passage using computational fluid dynamics (CFD) under steady-state conditions. Building upon prior research, we further investigate the impact of an uneven gap distribution caused by radial co-directional installation deviations of 0.1 mm, 0.3 mm, 0.5 mm, 1.5 mm, and 2.5 mm on the pressures and radial forces at various locations of the turbine, including the upper crown chamber, the vaneless zone, and the bottom ring chamber, all under steady-state rated operating conditions. By examining the maximum and minimum pressure values under different conditions, we determined that different pressure reading methods should be applied to distinct surfaces. Additionally, we derived the patterns illustrating how different components are affected by radial installation deviations. The significance of this study lies in its comprehensive exploration of the influence of radial installation deviations on the performance of a Francis turbine, particularly under steady-state rated conditions. Through numerical analysis, we elucidated the specific effects of various deviation magnitudes on the pressures and radial forces at different turbine locations. These findings provide valuable insights for the optimization of turbine design and operation. The novelty of this work stems from its in-depth investigation of radial co-directional installation deviations and the extensive results obtained through numerical simulations. These results hold significant implications for improving turbine performance and reliability, surpassing previous efforts in the literature. [ABSTRACT FROM AUTHOR]