Search Results (1,145)

Water-saving agricultural irrigation systems depend heavily on the hydraulic stability of pressure-compensating (PC) emitters, whose performance is fundamentally shaped by internal flow-path geometry. This study analyzes six commercial PC emitters (E1–E6) operated under pressures of 0.8–2.0 bar to quantify how key geometric descriptors influence hydraulic parameters critical for efficient water use, including actual discharge (q_act), discharge coefficient (k), pressure exponent (x), emission uniformity (EU), and flow variability. All emitters had discharge deviations within ±7% of nominal values. Longer and more tortuous labyrinths enhanced compensation stability, while emitters with wider cross-sections and shorter paths produced higher throughput but weaker regulation efficiency. Linear mixed-effects modeling showed that effective flow area increased k, whereas normalized path length and tortuosity reduced both k and x. Predictive equations derived from geometric indicators closely matched measured values, with deviations below ±0.05 L/h for k and ±0.05 for x. These results establish a geometry-based hydraulic framework that supports emitter selection and design in water-saving agricultural irrigation, aligning with broader Agricultural Water–Land–Plant System Engineering objectives and contributing to more efficient and sustainable water-resource utilization. Full article

This paper synthesizes lessons learned from drilling a CO₂-storage stratigraphic well in the San Juan Basin (New Mexico, USA) to clarify drivers of operational incidents and to inform future well planning. A literature review of regional drilling problems was combined with pre-drill engineering based on offset-well history and a geomechanical model, including casing, cementing, and hydraulics designs developed in commercial software; these designs were compared with field execution to extract incident-specific lessons. The most frequent problems observed are lost circulation, stuck pipe, and poor control of drilling parameters, consistent with complex lithology and reservoir pressure depletion that reduces fracture pressure below anticipated values. Based on the lessons learned, three mitigations are proposed as follows: (1) update the geomechanical model with the latest pore, fracture pressure estimates; (2) apply underbalanced drilling using nitrified mud by injecting nitrogen through a parasite string while drilling intermediate and production sections; and (3) maintain operating limits (weight on bit < 44.5 kN, top-drive rotation < 45 rpm, and pump rate < 1.32 m³/min) to improve fluid returns through low-fracture-pressure intervals. Simulation results support the applicability of the proposed solutions. Full article

This study investigates the mechanical characteristics of a multi-stage centrifugal pump rotor through fluid–structure interaction (FSI) analysis. A two-stage centrifugal pump equipped with back vanes on the trailing impeller is selected as the research object. Numerical simulations are performed based on the continuity equation and Reynolds-averaged Navier–Stokes (RANS) equations, with experimental data utilized to validate the numerical model’s accuracy. The internal flow field mechanisms are analyzed, and the effectiveness of two axial force calculation methods—formula-based and numerical simulation-based—for the rotor system is comprehensively evaluated. Employing an FSI-based modal analysis approach, the governing differential equations of motion are established and decoupled via Laplace transformation to introduce modal coordinates. Modal analysis of the pump rotor system is conducted, revealing the first six natural frequencies and corresponding vibration modes, along with critical speed calculations. The findings demonstrate that when the flow field near the back vanes exhibits complex characteristics, the formula-based axial force calculation shows reduced accuracy. In contrast, without back vanes, the hydraulic motion in the impeller rear chamber remains relatively stable, resulting in higher accuracy for formula-based axial force predictions. The calculation error between the two conditions (with/without back vanes) reaches 27.6%. Based on vibration mode characteristics and critical speed analysis, the pump is confirmed to operate within a safe region. The rotor system exhibits two similar adjacent natural frequencies differing by less than 1 Hz, with perpendicular vibration mode directions. Additionally, rotational speed fluctuations in the rotor system induce alternating critical speed phenomena when operating in this region. This study establishes a coupled analysis framework of “flow field stability–axial force calculation accuracy–rotor dynamic response”, quantifies the axial force calculation error patterns under different flow field conditions of a special pump type, supplements the basic data on axial force calculation accuracy for complex structure centrifugal pumps, and provides new theoretical insights and reference benchmarks for the study of hydraulic–mechanical coupling characteristics of similar fluid machinery. In engineering applications, it avoids over-design or under-design of thrust bearings to reduce manufacturing costs and operational risks. The revealed rotor modal characteristics, critical speed distribution, and frequency alternation phenomena can provide direct technical support for the optimization of operating parameters, vibration control, and structural improvement of pump units in industrial scenarios, thereby reducing rotor imbalance, bearing wear, and other failures. Full article

Reliable posture and loading characteristics detection of hydraulic supports is one of the indispensable factors to realizing the intelligentization of fully mechanized coal mining faces. Due to the complexity and dynamic nature of mining process, achieving real-time and accurate detection of the hydraulic support posture and load presents an exceptionally challenging task. Therefore, an interactive algorithm for evaluating the load-carrying characteristic of hydraulic support by considering the three-dimensional space driving theory and dynamic theory was developed and experimentally verified based on a self-designed experimental platform. The paper aimed to establish a three-dimensional spatial dynamic and kinematics model for shield support, evaluating its loading performance in challenging working conditions. Initially, a three-dimensional kinematics model was developed to describe the bearing capacity of powered support in various postures based on the three-dimensional drive space theory. A dynamic model was suggested to investigate the effects of multiple factors on the position of hydraulic support drive units on their load-carrying capability in various demanding working situations. The results indicate that increasing the length of the drive units can significantly improve the bearing performance of shield support. The proposed mathematical technique offers a novel method for modifying the coupling of surrounding rock with hydraulic supports and supplying coal mining with real-time assistance. Full article

Protecting aquatic biodiversity while ensuring reliable hydropower production and water supply remains a core challenge for both water security and biosecurity. In this PRISMA-based systematic review, we synthesize evidence from 96 studies on fish guidance and deterrence at hazardous water intakes. We examine non-physical barriers, including acoustic and light cues, electric fields, bubble curtains, and chemical stimuli, as well as physical barriers such as racks, guidance structures, and nets or screens that aim to divert fish away from intakes and toward selective passage routes. Overall, guidance and deterrence performance is strongly species- and site-specific. Multimodal systems that combine multiple cues show the highest mean guidance efficiency (~80%), followed by light-based deterrents (~77%). Acoustic, electric, and bubble barriers generally achieve intermediate efficiencies (~55–58%), whereas structural devices alone exhibit lower mean performance (~46%), with substantial variability among sites and designs. Physical screens remain effective for larger size classes but can increase head loss and debris accumulation. By contrast, non-physical systems offer more flexible, low-footprint options whose success depends critically on local hydraulics, the sensory ecology of target species, and ambient environmental conditions. We identify major knowledge gaps relating to underlying sensory and behavioral mechanisms, hydraulics-based design rules, and standardized performance metrics. We also highlight opportunities to integrate advanced monitoring and AI-based analytics into adaptive, site-specific guidance systems. Taken together, our findings show that carefully selected and tuned barrier technologies can provide practical pathways to enhance water security and biosecurity, while supporting sustainable fish passage, improving invasive-species control, and reducing ecological impacts at water infrastructure. Full article

To manage sewer networks, reliable data is needed, which is often challenging. This study proposes a novel methodology to reconstruct the sewer network topology using graph theory. Two core procedures—flow adjustment and edge addition—re-establish hydraulically consistent flow paths and restore connectivity in disconnected portions of the network by reversing and adding links. The proposed approach operates at the pipe level, repairing directional reachability. It leverages only the existing network topology to reconstruct connectivity, guided by the principle that every node must have a downstream path to an outlet. The methodology is first applied to reconstruct the sewer network of Montpellier Metropolis in the South of France. Then it is validated by deliberately removing and reversing edges and applying the algorithms to test the methodology’s capability in recovering the correct topology. Both methods performed well individually, especially at lower percentages of reversal (1%) and removal (1%), with a correctness of 0.99 for flow adjustment and 0.8 for edge addition. Although the results were poorer when combining the methods and increasing data degradation—particularly at 10% reversal and 10% removal (correctness of 0.64)—the methodology continued to produce a functionally consistent and logically coherent network, highlighting its robustness given the absence of supporting attribute data. Full article

As a key sustainable green-mining technology, ultra-high-water backfill mining is widely used to control surface subsidence and sustain extraction of constrained coal seams. Focusing on the Hengjian coal mine in the Handan mining area, this study uses physical modeling and industrial tests to clarify surface subsidence under different filling rates and identify the rock layers that hydraulic supports must control at various equivalent mining heights. A method is proposed to improve the filling rate by optimizing the thickness of the hydraulic support canopy through topological analysis. Results show that, compared with a filling rate of 85%, a 90% filling rate reduces subsidence of the basic roof, key layer, and surface by 51%, 57%, and 63%, respectively, while the industrial practice results have verified that the filling rate can significantly control surface subsidence. The equivalent mining height thresholds for instability of the immediate roof and high basic roof at the 2515 working face are 0.44 m and 1.26 m. Reducing the trailing beam thickness by 10 cm can theoretically raise the filling rate of the 2515 working face by about 2%, offering guidance for similar mines. Full article

A sand-laden vortex is a common phenomenon in marine engineering, particularly in coastal near-bed water intake and pumping facilities, and is widely recognized as an unfavorable factor affecting the safe and efficient operation of hydraulic machinery. The purpose of this study is to explore the energy characteristics of the development process of a sediment-laden vortex in the inlet pool. The research method is to use the V3V (Three-Dimensional Velocity Measurement System) to measure the three-dimensional velocity field of a sand-laden vortex, and analyze the energy characteristics of the evolution process of a sand-laden vortex in combination with energy gradient theory. The results indicate that in the early stage of vortex development, the turbulent kinetic energy of the sand-laden vortex gradually increases with time. After reaching its maximum value, the turbulent kinetic energy of the sediment-laden vortex continues to develop for about 0.4 s, then sharply decreases and completely dissipates within 0.3 s. The axial development speed of the vortex is closely related to the distance from the pump impeller. The energy gradient during the vortex evolution process indicates that the energy around the sand-laden vortex at different stages accumulates and dissipates as the vortex evolves. The research results of this article provide mechanistic insights into the evolution of a sand-laden vortex and offer theoretical support for sediment control and hydraulic optimization in marine and coastal pumping systems. Full article

River ice is a common natural phenomenon in cold regions during winter, and it is also one of the key factors that must be considered in the development and utilization of water resources in these areas. In this paper, based on a two-dimensional hydrodynamic model and ice dynamics model coupled with a linear thermodynamic process, this study simulates and validates the formation, decay, transport, and accumulation of river ice at the Toudaoguai reach of the Yellow River in Inner Mongolia during the winters of 2019–2020 and 2020–2021. The influence of different parameters on backwater level variations caused by ice jams is further investigated using a modified Morris sensitivity analysis method. The results show that (1) the coupled thermal-dynamic model can accurately simulate the formation, transport, and accumulation process of river ice in natural river, as well as the freeze-up patterns and corresponding hydraulic characteristics. (2) Due to the influence of river topography, flow rate, and flow density, the freeze-up form is slightly different in different years, and the low discharge process favor a more stable freeze-up. (3) According to the modified Morris screening method, discharge (Q) and ice concentration (N) are the most sensitive to the change in the backwater water level after the ice jam, and the sensitivity is more than 50%. The next most sensitive factor is the ice-cover roughness (n_i), whereas ice porosity (e_f) exhibits a negative sensitivity to the water level after ice jam. Thus, this study provides effective tools to reproduce the process of river ice transport and accumulation in the reach of the Yellow River (Inner Mongolia section) and offers technical support and insights for ice-flood prevention and mitigation in this section. Full article

Monitoring the stability of hydraulic structures such as dams and reservoirs in seismically active regions is essential for ensuring their safety and operational reliability. This study presents a comprehensive geospatial approach combining lineament analysis and geodynamic zoning to assess the structural stability of the Voroshilov and Priyut reservoirs located in the Almaty region, Kazakhstan. A regional lineament map was generated using ASTER GDEM data, while ALOS PALSAR data were used for detailed local analysis. Lineaments were extracted and analyzed through automated processing in PCI Geomatica. Lineament density maps and azimuthal rose diagrams were constructed to identify zones of tectonic weakness and assess regional structural patterns. Integration of lineament density, GPS velocity fields, InSAR deformation data, and probabilistic seismic hazard maps enabled the development of a detailed geodynamic zoning model. Results show that the studied sites are located within zones of low local geodynamic activity, with lineament densities of 0.8–1.2 km/km², significantly lower than regional averages of 3–4 km/km². GPS velocities in the area do not exceed 4 mm/year, and InSAR analysis indicates minimal surface deformation (<5 mm/year). Despite this apparent local stability, the 2024 Voroshilov Dam failure highlights the cumulative effect of regional seismic stresses (PGA up to 0.9 g) and localized filtration along fracture zones as critical risk factors. The proposed geodynamic zoning correctly identified the site as structurally stable under normal conditions but indicates that even low-activity zones are vulnerable under cumulative seismic loading. This demonstrates that an integrated approach combining remote sensing, geodetic, and seismic data can provide quantitative assessments for dam safety, predict potential high-risk zones, and support preventive monitoring in tectonically active regions. Full article

To enhance the sustainable power regulation capability of hydroelectric unit regulation systems (HURS) under modern power system requirements, this paper proposes an optimal linear quadratic regulator (LQR)-based power control strategy optimized using an improved Salp Swarm Algorithm (ISSA). First, comprehensive mathematical models of the hydraulic, mechanical, and electrical subsystems of HURS are established, enabling a unified state-space representation suitable for LQR controller design. Then, the weighting matrices of the LQR controller are optimally tuned via ISSA using a hybrid objective function that jointly considers dynamic response performance and control effort, thereby contributing to improved energy efficiency and long-term operational sustainability. A large-scale hydropower unit operating under weakly stable conditions is selected as a case study. Simulation results demonstrate that, compared with conventional LQR tuning approaches, the proposed ISSA-LQR controller achieves faster power response, reduced overshoot, and enhanced robustness against operating condition variations. These improvements effectively reduce unnecessary control actions and mechanical stress, supporting the reliable and sustainable operation of hydroelectric units. Overall, the proposed method provides a practical and effective solution for improving power regulation performance in hydropower plants, thereby enhancing their capability to support renewable energy integration and contribute to the sustainable development of modern power systems. Full article

The Survey Camera (SC) is the key instrument of the China Space Station Telescope (CSST), with its imaging performance significantly constrained by microvibrations from internal sources such as the shutter and cryocoolers. This paper proposes a systematic microvibration suppression scheme integrating disturbance source control, payload isolation, and transfer path optimization to meet the stringent requirements. The Cryocooler Assembly (CCA) compressor adopts a symmetric piston layout and a real-time vibration cancellation algorithm to reduce the vibration. Coupled with a vibration isolator designed by combining hydraulic damping and a flexible structure, it achieves a vibration isolation efficiency of 95%. The shutter adopts dual-blade symmetric design with sinusoidal angular acceleration control, ensuring its vibrations fall within the compensable range of the Fast Steering Mirror (FSM). And the finite element optimization method is used to optimize the dynamic characteristics of the Support Structure (SST) made of M55J carbon fiber composite material, to avoid resonance in the critical frequency bands. System-level tests on the integrated SC show that the RMS values of vibration force and torque within 8–300 Hz are 0.25 N and 0.08 N·m, respectively, meeting design specifications. This scheme validates effective microvibration control, guaranteeing the SC’s high-resolution imaging capability for the CSST mission. Full article

This study aimed to quantify and assess the spatial distribution of ²³⁸U, ²³²Th, and ⁴⁰K in the soils of the Espora Hydroelectric Power Plant (Espora HPP) and Queixada Small Hydroelectric Power Plant (Queixada SHPP) watershed (model hydraulic development areas) and their relationship with the geological, chemical, physical, and biological aspects of the soil. The study areas are located in the Corrente River drainage basin, in the southwestern portion of the state of Goiás, Brazil. Radionuclides were quantified using a PGIS-2 portable gamma spectrometer, with measurements taken at 21 sampling points. Soil samples were collected from the surface layer (0–20 cm) for particle-size and chemical analyses. The results indicated that the average radionuclide contents in the soils were 64.49 Bq/kg for ⁴⁰K, 45.44 Bq/kg for ²³⁸U, and 4.53 Bq/kg for ²³²Th. When comparing these values with the global average established by UNSCEAR, it was observed that ²³²Th and ⁴⁰K concentrations were below the global reference, whereas ²³⁸U concentration exceeded the world average of 33 Bq/kg. Particle-size characterization revealed significant variability in soil texture, with sand content ranging from 51.46 to 90.91%, clay content from 7.45 to 30.64%, and silt content from 1.64 to 17.90%. Organic matter content had an average of 10.09 g/kg, while soil pH ranged from 4.67 to 6.54. The results of this study have demonstrated the relevance of integrating radiometric and geochemical data for assessing environmental safety in hydroelectric development areas. The approach adopted can support monitoring programs and decision-making processes related to soil management and land-use planning in regions influenced by hydraulic infrastructures. Full article

Tuna-processing facilities produce substantial amounts of concentrated organic residues and sludges containing high levels of proteins, lipids, and nitrogen, which are not easily handled by conventional waste treatment methods. In this work, the anaerobic digestion (AD) performance of tuna-processing by-products (TPB1–2) and associated wastewater sludges (TWS1–3) was investigated using a combination of biochemical methane potential (BMP) tests, theoretical methane yield calculations based on the Buswell–Boyle equation, semi-continuous mono-digestion experiments, and 16S rRNA gene-based microbial analyses. Among the evaluated materials, TWS2 produced the highest methane yield (554.6 N mL CH₄/g VS) and, when its annual production volume was taken into account, showed the greatest estimated energy recovery (approximately 1.88 × 10⁶ kWh per year). By contrast, TWS3 exhibited the lowest methane yield (239.8 N mL CH₄/g VS), which was attributed to the presence of lignocellulosic sawdust and its limited biodegradability. TWS1 showed a moderate level of performance, with an estimated biodegradability of 62.3%, which may have been influenced by the addition of ferric salts and polymeric coagulants during sludge conditioning. In the semi-continuous digestion experiments, reactors that were initiated under relatively high total ammonia nitrogen (TAN) concentrations achieved stable operation within a shorter period, with the acclimation phase reduced by approximately one hydraulic retention time. These trends were supported by the microbial community data, where an increase in Bacillota-associated families, such as Tissierellaceae and Streptococcaceae, was detected along with a clear shift in dominant methanogens from Methanothrix to the more ammonia-tolerant Methanosarcina. Taken together, it is suggested that, when ammonia levels are appropriately managed, mono-digestion of tuna-processing sludges can be operated at a moderate organic loading rate. The process stabilization and energy recovery in nitrogen-rich industrial wastes are closely linked to gradual microbial adaptation rather than immediate improvements in methane yield. Full article

The use of flawed excavated-mass aggregates produced from crushing and screening hydraulic engineering waste in concrete projects can reduce natural resource extraction, increase waste utilization rates, and minimize environmental pollution. However, the direct application of flawed excavated-mass aggregates is limited due to their high crushing index and water absorption rate. Therefore, this paper measures the multi-dimensional physical and mechanical properties of defective aggregates. A strengthening slurry is prepared by comprehensively modifying the crystallization strength and penetration path of sodium silicate solution using various chemical reagents. The strengthening mechanism of the slurry on flawed excavated-mass aggregates is analyzed using SEM and MIP tests. Concrete tests are designed to investigate the workability and mechanical properties of flawed excavated-mass aggregate concrete. The pore structure of the ITZ (Interfacial Transition Zone) in defective aggregate concrete is analyzed through BSE (Backscattered Electron) imaging to elucidate the strengthening mechanism of secondary crystallization reactions on the ITZ. The research findings can provide technical support for repairing aggregates with defects. Full article