Hydraulic Structure Research Articles

Effect of Perforated Sills on Maximum Scour Depth Downstream From a Sluice Gate

Aims: Experiments were conducted to study the effect of using a perforated sill on maximum scour depth downstream from a sluice gate. Background: Previous studies have shown that screens may be utilized efficiently for dissipating the energy of water downstream of a hydraulic structure. Objective: For the present study, a series of experiments was conducted to investigate the effect of using a perforated screen sill on the maximum scour depth downstream of a hydraulic structure. Methods: In the present study, a single perforated sill with varying porosity (10.3%, 18.3%, 28.5%, and 41.1%) and an inclination angle of 90° were used. Perforated sill with different shapes of holes (circular, rectangular, and square holes) was used during the study. The major parameters for the present study are the porosity of the perforated sill, different shapes of holes, downstream water depth, and the Gate Froude number (FG) for a range covering from 2.15 to 4.7. The gate opening simulating a hydraulic structure is adjusted at heights of 4 cm, 5 cm, and 6 cm during the experiments work. Result: The results revealed that an increase in the sill porosity (Ao/As) increases the screen effect to reduce the max scour depth. In addition, the results showed that the sill with square holes is better than the sill with circular and rectangular holes in reducing the maximum scour depth. Conclusion: The perforated sill with a square porosity of 41.1% reduces the maximum scour depth downstream of a sluice gate by 60%.

Geoelectric Monitoring of Earthen Hydraulic Structure State by Resistivity and Induced Polarization Methods: Mine Water Settling Pond Dam Case Study

In earth dams, a permanent filtration of water leads to washing out of sand-clay fraction and to a formation of soil decompression sites, which pose a danger to embankment integrity. Condition monitoring of earth hydraulic structures can be executed by geophysical methods. The article presents the results of geoelectric monitoring conducted on the dam of settling pond of mine water with high metal content. The investigations were carried out by vertical electrical soundings, including electrotomography, and by methods of induced polarization in time and frequency domains. According to the results of the electrical soundings, places of reduced soil resistivity in the dam were identified, associated with infiltration of precipitations and of water from the pond. Geoelectric monitoring showed changes of the soils resistivity in different years, depending on hydrological conditions. Induced polarization methods are sensitive to material composition of soils, such as clayiness and presence of electronically conductive minerals. It is determined that the highest content of clay is in the upper and middle parts of the embankment. In eastern part of the dam, intensive polarizability of the medium was detected. It can be caused by filtration of water, contaminated with metals, through the embankment and sedimentary rocks. Thus, by resistivity measurements, it is possible to identify areas of intensive filtration in the dam body, and induced polarization measurements make it possible to determine clay content in the soil and possible pathways of contamination through the dam, which is of great importance for studying the environmental situation of region.

Assessment of surface water resource and allocation optimization for diverse demands in Ethiopia's upper Bilate Watershed

Water planning and management is very crucial for all computing sectors for water uses to maximize the scarce and allocated water uses based on their demands sustainably in Ethiopia's upper Bilate watershed. The shortage of surface water, especially during dry months, has become a major point of contention between upstream and downstream water users in the upper Bilate River. Therefore, the key objectives of the study are to evaluate the surface water resources and determine the best distribution for a range of requirements in the watershed. The historical climatic and stream flow daily data for the period of 2010–2019 have been used for the analysis. Hydrologic Engineering Center Hydrologic Modeling System-Geospatial Hydrologic Modeling Extension with the Hydrologic Engineering Center Hydrologic Modeling System was used for rainfall-runoff analysis. The model output further represents that the yearly overall surface water of the watershed is 502 MC M. Estimated annual environmental requirement is 75.32MCM which is 15% of the average annual available flow in watershed. Current annual irrigation, livestock, and domestic water demand were estimated to be 19.34 MC M, 12.39 MC M, and 79.4 MC M, respectively. The net amount of water delivered was 19.25 MC M, 79.28 MC M, and 12.36 MC M for irrigation, domestic, and Livestock demands, respectively, in the reference scenario. In the currently available (reference) scenario, 99.8% of the water supply need had been fulfilled, yet only 0.2% of the requirements for water were unmet. Average annual water demand of 111.13 MC M in the current scenario growth to 176.08 MC M when the future growth scenario. In contrast, for the future irrigation development and population projections scenario, 69.8% of the supply-demand became acquainted, and 30.2% of the demand for water remained unfulfilled in 2035. Therefore, to realize good water availability for productive use and allocate water optimal manner constructing a hydraulic structure (dam) upstream of the watershed was recommended.

Vapour pressure deficit modulates hydraulic function and structure of tropical rainforests under nonlimiting soil water supply.

Atmospheric conditions are expected to become warmer and drier in the future, but little is known about how evaporative demand influences forest structure and function independently from soil moisture availability, and how fast-response variables (such as canopy water potential and stomatal conductance) may mediate longer-term changes in forest structure and function in response to climate change. We used two tropical rainforest sites with different temperatures and vapour pressure deficits (VPD), but nonlimiting soil water supply, to assess the impact of evaporative demand on ecophysiological function and forest structure. Common species between sites allowed us to test the extent to which species composition, relative abundance and intraspecific variability contributed to site-level differences. The highest VPD site had lower midday canopy water potentials, canopy conductance (gc ), annual transpiration, forest stature, and biomass, while the transpiration rate was less sensitive to changes in VPD; it also had different height-diameter allometry (accounting for 51% of the difference in biomass between sites) and higher plot-level wood density. Our findings suggest that increases in VPD, even in the absence of soil water limitation, influence fast-response variables, such as canopy water potentials and gc , potentially leading to longer-term changes in forest stature resulting in reductions in biomass.

Investigation of effect lengths and angles of the control devices below the hydraulic structure

Abstract This study investigated the effect of reducing seepage under a hydraulic structure. This article aims to find positional equations for the control devices that reduce the seepage under the hydraulic structure. Using lengths and angles of sheet-piles under the hydraulic structure where the sheet-pile was placed up- and downstream, respectively, upon the hydraulic structure with anisotropy soil hypothetically affects both uplift pressure and seepage values. The experiments were conducted in two cases: in the first case, a couple of sheet-piles were oriented to the upstream passage; while in the second case, they were oriented to the downstream. Then, the second case was compared with three sheet-piles placed upstream, downstream, and intermediate to the passage. For each experiment (at the hydraulic toe position), the major affecting parameters such as the uplift pressure, gradient exit, and outlet flow rate were found. A correlation equation to correlate the exit gradient and discharge parameters was developed.

Discharge estimation using brink depth over a trapezoidal-shaped weir

A weir is an accurate hydraulic structure for estimating water discharge in open channels and rivers. It can be constructed with a standard shape with vertical upstream and downstream faces or it can be modified by inclining one or both weir faces to enhance its hydraulic characteristics. In this study, the feasibility of using the brink depth over a trapezoidal-shaped weir (yb) for discharge estimation was experimentally investigated for free flow conditions. The experimental work involved the use of three lengths of the weir crest, L (10, 20, and 30) cm, and four different slopes (37°, 54°, 75°, and 90°) for both upstream and downstream faces, each with different water discharge. In addition, the effect of channel bed slopes on the water head over the weir (h) and the brink depth (yb) was investigated. The results indicated that the (yb) can be used for discharge estimation with good accuracy for a trapezoidal-shaped weir instead of water head over the weir (h), which is usually used in estimating water over the weir, as (yb) does not affect by the channel bed slope and insignificantly affected by changing the upstream and/or downstream face angle, contrary to the (h). Hence, an empirical equation for estimating water discharge based on (yb) with different upstream and downstream slopes was developed and examined using some available previous studies data. The mean absolute percentage error (MAPE) between (yc/L) with (yb/L) and between the measured and estimated discharge is 4.73% and 7.02%, respectively.

О структуре гидравлических потерь при работе многоступенчатых лопастных насосов

The paper proposes methodology for assessing hydraulic resistance of the vane pump stages. The methodology makes it possible to reveal the hydraulic losses structure during liquid pumping and assess contribution of each type of these losses to the overall balance of the pumping stage energy consumption. Dependence of hydraulic losses on the width of the inter-vane flow channels is shown. Theoretical method was developed to predict the effect achieved by altering the vane design and production technology. Prospects of research, design, development and industrial production of the new type of multistage vane pumps with the oval-type stages are substantiated.

Mathematical modeling of the geomechanical stateof a manufactured rock mass under the conditionsof seismic loading

The aim of the study is to predict the geomechanical stability of the bottom slope of the operating tailing dump PJSC ArcelorMittal Kryvyi Rihunder the conditions of the main and emergency load combination. Research methods. The geomechanical stability of the tailing dump bottom slope under seismic loading was assessed based on the results of numerical modeling of hydrodynamic and geomechanical processes using the Phase2 software package implemented on the basis of the finite element method for two-dimensional analysis of the stress-strain state of loaded rock masses. Research results. Based on the analysis and synthesis of data on geological, hydrogeological, engineering, geological and technical conditions of the tailings slope, a predictive assessment of the hydrodynamic regime of the tailings slope was performed in accordance with the adopted scheme of its expansion and the geomechanical stability of the tailings slope under the action of the main and emergency combination of loads was determined. Based on the results of the calculations, the measures and technical solutions aimed at ensuring the normalized stability of the tailing dump are substantiated. Scientific novelty. The dependence of the geomechanical stability of the hydraulic structure on the physical condition of the rocks stored in the tailings dump and the nature of their watering under seismic loading was established, which made it possible to substantiate measures to ensure the stability of the tailings dump's lower slope, which consist in organizing the efficient operation of individual structures and elements of the drainage system, as well as excluding the storage of rock material with reduced filtration permeability in the contour zone of the upper part of the tailings dump slope. Practical significance. The results of the performed research form the basis for substantiating technical solutions to ensure the stability of hydraulic structures under seismic loading.

Hydraulic Traits in Populus simonii Carr. at Stands of Categorized Ages in a Semi-Arid Area of Western Liaoning, Northeast China

Poplar plantations can acclimate to drought stress in semi-arid areas, where the variation of stand age may result in varied water adaptation strategies presented as hydrodynamic performance. In this study, nine mature Populus simonii Carr. individuals were targeted as sampling objects in plantations characterized to three stand ages: young (9 yr), middle-aged (17 yr), and near-mature (29 yr) stages in a semi-arid area of western Liaoning, Northeast China. Hydraulic traits were investigated as parameters of leaf pressure-volume curves, xylem embolism vulnerability curves, hydraulic structure, and wood density (WD). Results showed that osmotic potential (Ψtlp) and relative water content at the turgor loss point and cell-wall bulk elastic modulus were lowest in middle-aged stands (−2.19 MPa; 86.71%; 13.75 MPa). Stem and leaf-specific hydraulic conductivity (Ks and LSC) were all the highest in middle-aged stands. Xylem embolism vulnerability (P50) and lethal water potential of trees (P88) increased with the growth of stand age. Young stands faced minimal risk of hydraulic failure according to the stomatal safety margin (SSMtlp, Ψtlp minus P50), which was consistent with the comprehensive evaluation results of the principal component analysis. WD was related to P88 (R2= 0.51; p < 0.05). P50 was related to drought avoidance traits Ψtlp (r = 0.76; p < 0.05) but not to xylem efficiency (Ks). Overall, WD can be an excellent proxy for hydraulic safety monitoring. Young and middle-aged Populus simonii populations are more adaptable to drought conditions than near-mature populations, and near-mature stands should receive intermediate cuttings to avoid exposure to drought stress.

Look at the past, vision for the future with the groundwater sustainability approach in desert regions

Ancient civilizations long practiced sustainable and integrated water resource management. To implement groundwater sustainability policies and strategies, this study introduces ecological wisdom as a transdisciplinary integrated approach. The present study aims to present strategies for the development and evolution of ecological wisdom governing Qanat hydraulic structure (QHS) with the groundwater sustainability approach in an Iranian desert region. Thus, the constraints of the development and evolution of ecological wisdom governing QHS were extracted using the structural-interpretive model, and the strategies for their development and evolution were presented with an operational-prescriptive approach. The results indicate that 14 variables can be identified as strategic constraints for the development and evolution of QHS. Also, based on eleven extracted scenarios with strong consistency, only two highly adaptable scenarios would design strategies for developing and evolving ecological wisdom governing QHS. Therefore, Rethinking the ancient heritage and developing ecological wisdom which governs it not only manifests the ecological considerations and cultural-social values of local communities but also considers a comprehensive and transdisciplinary approach to addressing materialism and reductionism challenges as well as providing a pattern for making visible the invisible treasure and groundwater sustainability in dry regions

Hydraulic parameters optimization of two-stage PDC bit in deep formation applications

Two-stage PDC (Polycrystalline diamond compact) bit is a special drilling bit consisting of a small-diameter pilot and a large-diameter reamer. The unique rock-breaking structure is designed to improve drilling efficiency and reduce drilling costs in deep and abrasive formations. According to previous studies, the hydraulic structure of the two-stage PDC bit can significantly affect the drilling performance of removing cuttings near the bottom of the wellbore. Therefore, this research has proposed to achieve high efficiency of cuttings removal by optimizing the hydraulic structure. In this paper, the flow field at the bottom of the well near the two-stage PDC bit (Φ171.45 mm pilot + Φ215.9 mm reamer) has been numerically studied using the finite element method. As shown in the analysis results, both the flow rate of the pilot and the flow rate ratio of the pilot to the reamer increase significantly with the increase of the area ratio of the pilot nozzles to the total nozzles. The numerical data supports that the cuttings can be removed effectively from the bottom of the wellbore when the area ratio is between 0.75 and 0.80. Moreover, the cuttings can be removed effectively from the bottom of the wellbore when the mud viscosity is about 10 mPa s, the rate of penetration is between 4 and 8 m/h, the drill speed is 90 rpm, and the cuttings particle sizes is between 1 and 2 mm. Besides, increasing the pump rate can improve the cutting-carrying efficiency through the wellbore bottom. Field test results indicate that the average penetration rate of the optimized bit is increased by 47.17% and the footage of the optimized bit is increased by 95.40% compared to the equivalent formation in adjacent wells. This study can provide guidance for the optimal design of the hydraulic structure of such two-stage PDC bits.

Simulation–Optimization Approach for Optimal Cut-Off Design Under the Hydraulic Structure

Simulation–Optimization Approach for Optimal Cut-Off Design Under the Hydraulic Structure

Gridded Precipitation Datasets and Gauge Precipitation Products for Driving Hydrological Models in the Dead Sea Region, Jordan

The consistency of hydrological process modeling depends on reliable parameters and available long-term gauge data, which are frequently restricted within the Dead Sea/Jordan regions. This paper proposes a novel method of utilizing six satellite-based and reanalysis precipitation datasets, which are assessed, evaluated, and corrected, particularly for the cases of ungauged basins and poorly monitored regions, for the first time. Due to natural processes, catchments fluctuate dramatically annually and seasonally, making this a challenge. This variability, which is significantly impacted by topo-geomorphological and climatic variables within the basins themselves, leads to increased uncertainty in models and significant restrictions in terms of runoff forecasting. However, quality evaluations and bias corrections should be conducted before the application of satellite data. Moreover, the hydrological HEC-HMS model was utilized to predict the runoff under different loss methods. Furthermore, this loss method was used with an integrated model that might be efficiently employed when designing hydraulic structures requiring high reliability in predicting peak flows. The models’ performance was evaluated using R-squared (R2), the root mean square error (RMSE), the mean absolute error (MAE), and Nash–Sutcliffe efficiency (NSE). In addition, these statistical metrics were implemented to quantitatively evaluate the data quality based on the observed data collected between 2015 and 2020. The results show that AgERA5 exhibited better agreement with the gauge precipitation data than other reanalysis precipitation and satellite-based datasets. The results demonstrate that the data quality of these products could be affected by observational bias, the spatial scale, and the retrieval method. Moreover, the SC loss method demonstrated satisfactory values for the R2, RMSE, NSE, and bias compared to the IC and GA loss, indicating its effectiveness in predicting peak flows and designing hydraulic structures that require high reliability. Overall, the study suggests that AgERA5 can provide better precipitation estimates for hydrological modeling in the Dead Sea region in Jordan. Moreover, integrating the SC, IC, and GA loss methods in hydraulic structure design can enhance prediction accuracy and reliability.

Estimation in jet deflection angle of deflector on the chutes

ABSTRACT Ski jumps are commonly used to discharge flow away from release structures into downstream rivers for energy dissipation. However, due to large intersection angles of jet and river flow or the jet impacting position unreasonable, the serious sour of riverbed or bank may occur, threatening the security of hydraulic structure. Hence, the impacting position and direction of jet from ski jump are pressing for research. For obtaining a controllable and desired outflow condition, adding rectangular tetrahedral deflector is a common and effective measure to change the flow direction. In this study, physical experiments and numerical simulation were conducted and the effect of the deflector contraction ratio on the flow deflection angle was revealed. The results indicate that the contraction ratio is a key parameter of the deflector, and a larger contraction ratio contributes to a larger jet deflection angle. Based on the data in the present and previous studies, a new empirical expression for estimating the deflection angle is proposed for rectangular tetrahedral deflector. By contrast with previous research, the calculated result from the expression presents a better agreement with the test data.

Research of the deformation state of the base of low-pressure hydraulic structures

This article discusses the results of field research to determine the deformation of the base of a low-pressure hydraulic structure that has been in operation for a long time. On the basis of geodetic measurements, a longitudinal profile of the settlement of the body of the structure was constructed, which ensures the safety of the foundation of the structure. A technique for carrying out field studies is presented, which makes it possible to control the deformation of the base in low-pressure hydraulic structures.

Experimental Simulation of Interaction Between Weir – Gate Hydraulic Structure and Dikes

Experimental Simulation of Interaction Between Weir – Gate Hydraulic Structure and Dikes

An analytical model for variation of exit gradient downstream of a hydraulic structure with inclined downstream cutoff resting on infinite anisotropic soil

ABSTRACT An analytical solution is developed for the variation of the exit gradient along the downstream side of hydraulic structure with downstream-inclined cut-off resting on an anisotropic soil. The model is presented using dimensionless variables to demonstrate the relationship between the exit gradient rate and the ratio of the cut-off length to the seepage driving head (Ie*S/h), as well as the ratio of the distance from the structure toe to the cut-off length (X/S). Various ratios of the dam base length to the length of cut-off (b/S = 2, 3, 5, 10, and 15) are considered, along with different degrees of anisotropy of the underneath soil (Kr = 1, 0.5, 0.25, and 0.1). A MATLAB code is developed to implement the model. The results indicate that the maximum exit gradient is observed at an inclination angle of 75°, while the minimum exit gradient is observed at a 30° cutoff inclination angle for all cases. The variation of the exit gradient exhibits an increasing linear trend from X/S = 0 up to a certain distance (between 1 and 2). Beyond this distance, a non-linear decreasing trend is observed. The relationship between the exit gradient and the inclination angle cases after a distance of approximately 5X/S. The range of maximum exit gradient decreases with a decrease in the degree of anisotropy (Kr); with a significant reduction observed for Kr values of 0.25 and 0.1. Furthermore, for all degrees of anisotropy, the range of maximum exit gradient decreases as b/S increases.

Research on the Prediction Method of Braking Rotation Angle for Remote-Controlled Excavator.

To calculate, analyze, and predict the rotation angle during the deceleration and braking process of large remote-controlled excavators, this article established a spatial coordinate system based on a simplified model of a hydraulic excavator's upper structure. Using the D-H parameter method, a mathematical model of the working device's center of gravity and its rotational inertia was established. Based on the characteristics of the excavator's hydraulic system and the relationship between brake torque variations, a prediction model was developed to forecast the stopping position (brake rotary angle) of the excavator's bucket after braking. Subsequently, the predicted results were validated using simulation and compared with existing experimental data to assess the accuracy of the model. The findings demonstrate that the predictive model exhibited high precision with minimal error. The utilization of this model enabled effective forecasting of the excavator's braking position changes, providing a theoretical foundation for the intelligent remote control of excavators.

Review on the durability of eco-friendly engineering cementitious composite (ECC)

A comprehensive manual review of the use of slag and fly ash in engineered cement-based composites (ECBCs) was conducted. The extensive use of supplementary cementitious materials and integrated fibers in engineered cement-based composite (ECBCs) in seawater composite structures can help to enhance the durability of infrastructure in marine environments and minimize the extensive use of cement and CO2 emissions in the construction industry. This paper retrieved journal and review articles on slag/fly ash utilization in ECBCs from the Scopus database, mainly from 2015 to 2022, and performed an analysis using a suitable software tool. It also provided an up-to-date review of the literature on eco-friendly engineered cementitious composites’ (ECC) durability, with in-depth discussions on the effects of temperature fluctuation on ECCs, supplementary cementitious material, frost and salt corrosion resistance, pre-cracking, seawater resistance, and microstructural alteration. The durability of ECCs is closely related to the behaviors of the fiber distribution, matrix, and fiber-matrix interface under various environmental conditions. The main factors causing the deterioration of the engineering cement-based composites are fiber orientation and dispersion, frost resistance, corrosion, and alkaline environment. Fiber dispersion is mainly assumed to be highly homogeneous in theory, but in practice, due to the uneven dispersion of the fibers the property of each composite structure is not uniform. Further, among all issue associated with durability, sulfate salt attack considered as the most significant environmental deterioration process that affect the resilience of hydraulic structure. At last, it is necessary to conduct additional research on the durability of ECC under various environmental conditions to comprehend its behavior in the actual world. The experimental data currently available on the short-term durability of ECC fluctuate over time. Which indicates that the mechanisms for the long-term degradation of ECC under specific environmental conditions remain unknown.

Seepage Analysis and the Reservoir Water Pollution Potential under Vertical Dam Structure Planning

A prospective resolution to the intricate predicaments of flooding, sanitation, and the availability of unprocessed water for the populace of Jakarta residents is the implementation of the coastal reservoir paradigm. This paradigm entails harnessing the latent capacity of the Cisadane River flow and its subsequent storage within a retention pond, and then subjecting it to reprocessing to serve as a viable source of raw water. The selection of a vertical seawall design was based on the objective of creating an effective barrier between the reservoir and the sea, while also considering several environmental factors. This design was selected with the aim of minimizing the need for extensive soil excavation and rock placement. However, it is important to note that the risks of construction failure associated with seepage under hydraulic structure and dam stability pose significant challenges. Besides preventing saltwater intrusion and maintaining the integrity of the reservoir as a freshwater source, dam must be designed to mitigate potential seepage failure and intrusion issues. To address these concerns, this study employed numerical simulation using the SEEP/W and CTRAN/W software. The simulation was carried out to analyze seepage discharge under a vertical dam and predict potential seawater intrusion into the reservoir. The dam was examined over a ten-year period, with varying embankment widths of 10m, 20m, and 30m. The analysis considered changes in water level (ΔH) and the addition of a cut-off wall at depths of 5m, 10m, and 15m. The obtained results showed that seepage discharge rates amounted to 3,14x10-4 m3 s-1, 2,67x10-4 m3 s-1, and 2,50x10-4 m3 s-1 for embankment widths of 10m, 20m, and 30m, respectively, under a 1m level difference condition. Following this, the safety factor for piping on vertical embankment was determined as 1.10, 1.34, and 1.39 for widths of 10m, 20m, and 30m, respectively. This factor was found to increase to 4.03 when the embankment distance was widened, and a 15m deep cut-off wall was installed. It is important to note that the seawater intrusion model predicted a seawater concentration of 65,12 g m-3 at the bottom for an embankment width of 10m, while no intrusion was observed at widths of 20m and 30m with ΔH=1m. This study aims to assess potential risks of piping due to seepage and seawater contamination at the Cisadane Estuary.