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This article presents the effect of biological clogging on the hydraulic performance of geotextiles used for the construction of filter and drainage in landfills. Clogging tests were performed on specimens of woven and non-woven geotextiles in a discontinuous fermentation scenario using natural leachate and a nutrient solution. The consequences of biological clogging were assessed through experimental measurements of changes in the cross-plane hydraulic conductivity and the impregnation ratio of different geotextiles specimens at different immersion times. Porosity reduction was then back-calculated from the hydraulic conductivity results using the Kozeny-Carman equation. Additionally, the impact of an antibiotic and antifungal solution on biofilm development was evaluated. It was demonstrated that the cross-plane hydraulic conductivity of geotextile specimens decreases as biomass accumulation per unit area increases with immersion time. The application of an antibiotic and antifungal solution resulted in a porosity recovery of over 90% and a hydraulic conductivity recovery ranging from 78 to 83% for both woven and non-woven geotextiles. These results demonstrate that the clogging was primarily due to biological activity. Despite certain limitations in measurement and definition, the impregnation ratio proved to be a reliable parameter for the evaluation of biological clogging. • Bioclogging of geotextiles employed in filter and drainage layers was analyzed. • Influence of geotextile type on biological clogging was determined. • Biofilm formation in geotextile specimens was quantified. • Porosity reduction was determined using hydraulic conductivity models. [ABSTRACT FROM AUTHOR]

Due to the complexity of open-channel networks in which a lengthy procedure is required to understand and analyze their behavior. This paper introduces a methodology for the skeletonization of complex tree-shaped open channel systems. The aim is to aggregate separate branches into one equivalent branch, which has a new skeletonization factor. Three different illustrative examples of river systems using two approaches are analyzed. The software package HEC-RAS is employed to simulate the proposed open channel networks as a one-dimensional steady, gradually varied flow state. Results show that there is a strong correlation between the skeletonization factor required for the equivalent branch and the flow rate of the equivalent branch. The skeletonization factor is also significantly affected by an increase in the ratio of the bed width of each branch canal to that of the main channel in Approach A. The water depth along the main channel has increased more significantly in approach B than in approach A, with average increases of 49.5 %, 29.2 %, and 14.1 % for a number of branches equal to 2, 4, and 6, respectively. Finally, the developed skeletonization concept can be used to represent complex open-channels network models. [ABSTRACT FROM AUTHOR]

A new type of small, dry-filled geotextile tubes is introduced, that, in a stacked formation, can be used as dike cores. Dikes made out of these tubes consist of great potential regarding more resilient flood protection. The geotextile protects the fill from erosion, enabling steeper slopes along with reduced material and less land consumption. The behavior and potential failure mechanisms of such dikes were investigated first by literature research and second by full-scale hydraulic model tests under systematic variation of tube number, number of textile layers, filling ratio, and fill material. The tubes were exposed to the loads of seepage and overflow. Most relevant failure mechanisms were seepage-induced sagging, lateral displacement, and overturning of the upper tube due to overflow. During seepage, the tube height was reduced by up to 22.8 % due to sagging. Overflow led to a lateral displacement of up to 13 cm and, at overflow heights of 23.1 cm and 26.8 cm, to overturning of the upper tube. The present results give new insights into the behavior of innovatively constructed geotextile tubes under hydraulic loads and serve as basis for the development of design rules. • Dry-filled geotextile tubes represent a promising way towards resilient river dikes • Tube behavior is investigated experimentally under parameter variation • Sagging and lateral deformation must be considered in design rules • The tubes withstand overflow heights of >20 cm • Compacting the tubes increases the stability [ABSTRACT FROM AUTHOR]

The biofilm in-situ remediation is one of the most important and practical techniques for river remediation. The biochemical function of biofilms and the hydraulics of the river are both significant aspects of river remediation study, however, they belong to distinctive research points. To date, little research has combined the biochemical process of biofilm and the hydraulics of the river. In this study, ammonia oxidation rate (AOR) was used to characterize the activity of biofilms and measured at different flow rates. It was increased with the flow rate increasing before the peak (26.13 g-N/m3/h) at 0.3 m/s and then decreased to 0 at 0.414 m/s directly. Meanwhile, the skewness equation of flow rate (Fr) − AOR was established based on previous hydraulics and biology research. The kinetic parameters of the equations were determined by fitting the measured values of AOR (R2 > 0.95), which could be used to simulate the AOR of the river simulators and open channels. Besides, the distribution characteristics of the AOR at various flow rates in different sections were obtained. Overall, this paper provides a novel perspective by studying the internal biochemical model of biofilm and the hydraulic model with multiple influencing factors further to improve the biofilm-hydraulics coupling model. • Ammonia oxidation rate (AOR) in the riverway biofilm in-situ remediation was measured at different flow rates. • The quantitative description of the flow rate (Fr)- AOR relationship was established. • The AOR values at different sites of the open channel section were simulated and analyzed. [ABSTRACT FROM AUTHOR]

This research paper presents an integrated approach in dealing with the hydraulic models to investigate the impact of the reinforcement and maintenance work of the hydraulic structures, and presenting a case study of the El Bagoureya Regulator. The reinforcement works for El Bagoureya Regulator include the regulator's stilling basin, which will have to be filled with a reinforced concrete mattress, the extension of the central piers to the end of the winged wall, and finally the construction of a new concrete weir at the end of the winged wall downstream of the regulator. During the rehabilitation works, the flow will therefore pass through the navigation channel of the lock. The aim of the study is therefore to investigate the lock capacity to allow the maximum flows through at constant water levels and to meet the water demand. The study also examines the efficiency of the proposed solution and the impact on the hydraulic condition of the canal. The required protection and dredging both upstream and downstream of the lock were also studied. Therefore, A 2D numerical hydraulic model was integrated with a physical model at an appropriate scale as a near-field model. The results show a good correlation between the two models. The physical model confirmed the results of the numerical model and guaranteed the hydraulic efficiency of the proposed reinforcing structure. The results show that the proposed reinforcement works improved the flow pattern and the distribution of the flow velocity downstream of the pressure regulator. It also confirms that the navigation lock is capable of handling the high discharge during the rehabilitation works while maintaining the same operating water level. Finally, the physical model has ensured the stability of the proposed protection of the bottom upstream, downstream the navigation lock and downstream the regulator at the end of the stilling basin. [ABSTRACT FROM AUTHOR]

During the excavation of tunnels, many hazards caused by the fracture zone and groundwater seepage are often encountered. Studying the surrounding rock’s stability in the fracture zone of the mountain’s water-rich tunnels is thus crucial. The rock mass’s seepage and stress fields were studied by using the seepage theory of rock mass and Darcy’s rule in the experiment, and a hydraulic coupling model of porous continuum was constructed according to the coupling relationship between them. After that, the experiment used FLAC3D software to conduct three-dimensional numerical analysis of the tunnel, and analyzed the surrounding rock’s stability under different conditions. The findings demonstrate that the model’s error rate is just 0.16% and that the surrounding rock’s stability is influenced by the excavation plan, main support, and grade of the surrounding rock. Therefore, the model considers various factors for tunnel excavation and can be applied to the prediction of actual mountain tunnel construction. During the excavation of tunnels, many hazards caused by the fracture zone and groundwater seepage are often encountered. Studying the surrounding rock’s stability in the fracture zone of the mountain’s water-rich tunnels is thus crucial. The rock mass’s seepage and stress fields were studied by using the seepage theory of rock mass and Darcy’s rule in the experiment, and a hydraulic coupling model of porous continuum was constructed according to the coupling relationship between them. After that, the experiment used FLAC3D software to conduct three-dimensional numerical analysis of the tunnel, and analyzed the surrounding rock’s stability under different conditions. The findings demonstrate that the model’s error rate is just 0.16% and that the surrounding rock’s stability is influenced by the excavation plan, main support, and grade of the surrounding rock. Therefore, the model considers various factors for tunnel excavation and can be applied to the prediction of actual mountain tunnel construction. [ABSTRACT FROM AUTHOR]

Short-term microfiltration (MF) fouling is commonly abated by periodically reversing the flow to remove foulants that weakly adhered to the membrane. Strong oxidants (i.e., chlorine) can be added to hydraulic backwash water to augment its efficacy—a process called chemically enhanced backwashing (CEB). Herein, we report a rigorous mathematical model for constant flux MF incorporating hydraulic backwashing and CEB, and validate it with laboratory data obtained using untreated and alum-coagulated water from the Foss Reservoir in Oklahoma, USA. We implemented an optimal control procedure and used it to predict MF behavior long past experimental timescales. We identified a frequency threshold beyond which the necessary transmembrane pressure (TMP) reached an asymptotic value, indicating a pseudo steady-state, periodic solution to the model when coupling hydraulic backwashing with CEB. We report differences in TMP saturation values and timescales by simulating transient MF of untreated and pretreated water. Numerical simulations revealed that the operating flux could be increased 10-fold after pretreatment (compared with raw water) before reaching the maximum manufacturer-recommended pressure for the hollow-fibers. The predicted higher flux and extended duration between cleaning-in-place demonstrated advantages of coagulation pretreatment under hydraulic backwashing and CEB. Model observations could guide decision making for CEB timing and frequency. [Display omitted] • Microfiltration model derived with hydraulic and chemically enhanced backwashing. • Quantitative comparisons with experiments for raw and coagulated surface water. • Predictions of long-term productivity at various flux and backwashing conditions. • Different chemically enhance backwashing thresholds and timescales for pressure plateaus identified. • Flux and pressure plateaus change linearly for coagulated water, non-linearly for raw. [ABSTRACT FROM AUTHOR]

[Display omitted] • Comprehensively analyses high and low resolution DEMs; MERIT Hydro, SRTM, LiDAR and local DEM for different gradients. • Highlights the methodology for developing a new terrain for a data-scare region considering the accuracy. • Systematically reviews the predictions of 2D flood model simulations for a study area with high and low gradients. • Analysis of original SRTM, original MERIT Hydro, modified SRTM DEMs and the new developed DEM in 2D flood simulations. Topography highly influences hydraulic model predictions. High-resolution Digital Elevation Models (DEM) are currently used in 2D flood modeling studies to create relatively more accurate flood inundation maps. However, the availability of high-resolution datasets, such as Light Detection And Ranging (LiDAR), remains limited due to cost constraints. Thus, low-resolution global datasets are utilized in data-scarce regions. Merging high and low-resolution terrain datasets will be an alternative approach to improve flood models, and comprehensive analysis of such merged DEMs is lacking. Thus, a new DEM (V-DEM) is developed in this study by incorporating available LiDAR, SRTM, local DEM, and river cross-sectional data. 2D unsteady hydrodynamic model predictions are analyzed using the V-DEM, existing low-resolution global datasets, SRTM and MERIT Hydro, and their modified versions. V-DEM was found to create flood flow predictions with a better Nash–Sutcliffe efficiency, significantly outperforming low-resolution global datasets. In addition, MERIT Hydro showed more than 50% improvement in the Nash–Sutcliffe efficiency over SRTM in flow discharge predictions. There is a 110% improvement in the Nash–Sutcliffe efficiency for hydrologically corrected SRTMs over the original SRTM. When SRTM is merged with LiDAR and hydrologically corrected, the predictions also showed an improvement of 146% over the original SRTM. Moreover, this study highlights that the vertical accuracy of terrain datasets has a more significant effect on the flood model predictions than the horizontal resolution, especially in the high and low-gradient regions of the study area. Overall, this study would benefit flood modelers in developing accurate DEMs, especially in the unavailability of high-resolution data for the entire study area. [ABSTRACT FROM AUTHOR]

• A sensor layout optimization method is proposed for the district heating network. • Pipe impedance has a crucial impact on the accuracy of hydraulic simulation. • Relative influence matrices are defined to describe the hydraulic characteristics. • Sensitivity analysis is conducted on the relative influence matrices. • The optimal sensor layout scheme can improve impedance identification results. Pipe impedance is a key parameter affecting the accuracy of hydraulic simulation models of the District Heating System (DHS). Using impedance identification methods to calibrate the hydraulic simulation model is a commonly used solution to improve the accuracy of simulation results. To further enhance the pipe impedance identification results, we propose a sensor layout optimization method for District Heating Network (DHN) based on sensitivity analysis. This method defines two concepts of relative influence degree of impedance on pipe flow and impedance on node pressure to describe the hydraulic characteristics of DHN, and then derives the calculation formula of relative influence matrices. Finally, sensitivity analysis is conducted on the relative influence matrices, and pipes and nodes with a larger sum of relative influence increments are selected as the installation locations of sensors to form an optimal sensor layout scheme. In case study, we apply the sensor layout optimization method to a DHS with a meshed network. Through numerical simulation, the performance of different sensor layout schemes on impedance identification results is evaluated. The research results show that, compared with not installing sensors on the DHN, the proposed sensor layout optimization method can improve the accuracy of impedance identification by 16.82%. [ABSTRACT FROM AUTHOR]

An explicit lumped mass method based on dynamical remeshing technique is developed to calculate the flooding dynamics of damaged ship. To calculate the motion of floodwater, which is modelled as a lumped mass, the algorithm involves dynamically splitting the volume mesh in the compartment into the water and air elements, contingent upon the amount of water and the inclination of water surface presenting at each time step. The water surface inclination is calculated explicitly through the projection operation of dynamic equilibrium equation of lumped mass. Moreover, the remeshing algorithm is used to update the face elements at the opening to improve the calculation accuracy of the water flow rate by the hydraulic model. The effectiveness of the present method is validated by simulating the transient and progressive flooding of a box-shaped barge with single and multiple compartments arrangement. The computed ship motion, water level in the compartment and movement of internal water are compared with the experimental counterparts. The benchmark results indicate that the proposed method can effectively and efficiently predict the flooding dynamics of damaged ship in calm water environment. • A dynamical remeshing method is integrated into the lumped mass model for damaged ship flooding. • The algorithm dynamically splits the mesh element into the water and air elements. • The computation efficiency is high due to fully explicit operation. • The computation accuracy is validated for the transient and progressive flooding simulations. [ABSTRACT FROM AUTHOR]

• The fundamental ROM concepts were applied to computational thermal hydraulics. • Reduced order surrogate models were constructed by linear regression, second-order polynomial fitting, and artificial neural networks. • The semi-intrusive reduced order modeling approach was applied to the pressure matrix solver in SPACE code. Reduced order modeling emerges as a valuable tool for addressing multi-query challenges in high-fidelity computational simulations, particularly in areas such as design optimization and uncertainty analysis. Given that computational costs pose a primary obstacle to leveraging multi-physics multi-scale integrated systems, achieving computational reduction without compromising calculation accuracy through reduced order modeling offers significant advantages. This study explores two hybrid approaches to reduced order modeling, specifically applied to nuclear thermal hydraulic accident analysis. The first approach involves constructing a reduced order basis through random sampling, followed by the development of surrogate models based on linear regression, second order polynomial regression, and artificial neural network to predict time dependent thermal hydraulic behaviors. The second approach utilizes the reduced basis to transform a solution module within a thermal hydraulic analysis code, assessing the feasibility of the intrusive reduced order modeling approach. A comparison between reduced order model predictions and full order model calculations yields promising results, elucidating applicable conditions and limitations of the proposed approaches. [ABSTRACT FROM AUTHOR]

• The fractional 2-group diffusion model with thermal hydraulic feedback is introduced. • Residual power series is implemented to solve the diffusion model. • Convergence and stability of the proposed method is proved. • Fourth order FD schemes are used for the spatial discretization at the core edges. In this work, fast and accurate semi-analytical solutions are presented for the two group space–time fractional neutron diffusion model with thermal–hydraulic feedback using computational method. Throughout a linear combination of the Caputo fractional power series, the fractional residual power series method (FR-PWS) is constructed for temporal calculations. A new computable recurrence relation is introduced to estimate the series coefficients in successive algebraic steps. Additionally, higher order finite different (FD) schemes are spatially employed at the core interior meshes and at the core boundary meshes for spatial discretization. It is proved that using these higher order FD schemes significantly improved the steady state calculations preserving the system complexity. Convergence and stability of the FR-PWS method is discussed. It is proved that the convergence order of the higher order FD schemes with different core divisions equals four while the convergence order with different temporal step sizes of the FR-PWS method is approximately 1 - α for 0 < α ≤ 1. The proposed method is applied simply to two- and three- dimensional space homogenous benchmarks. Then, the method is tested for heterogeneous benchmark reactors with step, ramp, and sinusoidal reactivities. Finally, the method is applied to solve LRA BWR benchmark reactor including adiabatic heating and Doppler feedback. It is proved that for heterogeneous reactors, the effect of the anomalous subdiffusion diminishes throughout the transient for all types of perturbations. [ABSTRACT FROM AUTHOR]

• The E-SCAPE facility is a 1/6 −scale model of the liquid–metal reactor MYRRHA. • A buoyancy-driven natural circulation flow establishes in decay heat removal mode. • The Richardson number indicates for thermal stratification in the upper plenum. Natural circulation in the primary system is the chosen option in terms of decay heat removal (DHR) for the liquid–metal cooled, pool-type research reactor MYRRHA, keeping temperatures in the core within the safety limits and maintaining structural integrity of the coolant boundaries. Experiments in E-SCAPE, the 1/6-scale 3-D model of the primary system of MYRRHA, demonstrate that in DHR conditions, a buoyancy-driven natural circulation flow establishes and is capable to remove the core power with temperatures that are within acceptable limits. The effects of the core power, the system pressure losses and the initial conditions on the flow and the temperatures are analyzed. The experiments show that, in natural circulation thermal stratification is present in the upper plenum. From forced circulation experiments in the same facility, one can conclude that good thermal mixing is obtained for forced flow rates above 40% of the nominal flow rate. Below this value, buoyancy becomes important and thermal stratification is observed in forced flow conditions as well. Results demonstrate that the Richardson number in the upper plenum Ri UP can be used as an indicator for thermal stratification. For values below unity, good thermal mixing is observed. If Ri UP is higher than 1, thermal stratification occurs. [ABSTRACT FROM AUTHOR]

Anthropogenic and natural weathering processes have produced submicron microplastics (MPs), an emerging contaminant. Due to small size, the treatment of submicron plastics particles by membrane processes requires small cutoff membranes, which necessitates great pressure gradient and suffers from clogging. The present study aims to develop an electrophoretic separation system for the separation of negatively charged submicron plastics particles from water. An electric field was supplied to produce an electrostatic force to counter the drag force in the permeation stream, thereby, preventing submicron plastics particles from entering the permeate. The critical electric field (E c) for complete particles removal was estimated based on the dilute-to-influent flow rate ratio (q d), zeta potential, and size of submicron plastics particles. The result showed that at steady-state, particle removal could reach 99 % at E > E c at q d = 0.5. The distribution of plastics particles during electrophoretic separation was analyzed considering electrophoresis and particle deposition. The particle removal efficiency can be modelled by hydraulic condition and critical electric field. Finally, the engineering aspects such as long-term operation, electrode degradation and influence of coexisted constituents were evaluated. The operation cost of electrophoretic separation was calculated to be USD 0.48/m3, which is cost-effective at small scales compared to conventional membrane processes. [Display omitted] • Electrophoretic separation successfully removes PS nanoplastics from water. • Zeta potential, cell geometry, and hydraulics control the critical electric field. • Electric field greater than critical value completely removes PS nanoplastics. • A model based on force field and mass balance well predicts removal efficiency. • Specific energy consumption is 5.0 kWh /m3 at dilute flow fraction of 0.5. [ABSTRACT FROM AUTHOR]

Urbanisation has resulted in rapid geomorphic changes and ecosystem degradation in many streams worldwide. The question of how channel response to urbanisation can be accurately predicted amid multiple driving factors remains a significant scientific challenge. Numerous efforts have been made to address this issue over the past 80 years. Nevertheless, channel response resulting from urbanisation differs across physiographic regions, making it difficult to predict. The main goal of this study is to investigate the most important factors influencing morphological changes, such as channel area, in streams with urbanised catchments. To accomplish this aim, we reviewed the literature on the application of hydraulic geometry models to urban-impacted rivers worldwide. We set out to investigate two specific questions: (i) to what extent and under what circumstances can urban stream bankfull cross-sectional area be predicted by catchment area and impervious cover metrics? and (ii) is stream bankfull width more susceptible than stream bankfull depth to urban-induced enlargement? However, over 90 % of the urban channels studied in the literature we reviewed showed irregular response patterns to urbanisation, owing to the complex interplay of local factors, such as geology, sediment, hardpoints, and riparian vegetation. Our most important conclusion is that local context is an important controller of stream channel response to urbanisation. While catchment area is a good predictor of channel area in some urban sites, it is a poor predictor of channel area in other urban sites. This contrasts with non-urban sites, where catchment area usually predicts channel area more strongly. In addition, impervious cover alone, which represents the direct hydrological impact of urbanisation, is insufficient to fully explain channel enlargement and incision. Therefore, models of channel response to urbanisation must consider the specific local factors that drive or limit these responses in order to be effective as predictive and explanatory tools. • Local context significantly controls stream channel response to urbanisation. • Catchment area is an inconsistent predictor of channel area in urban sites. • Impervious cover alone is insufficient to fully explain channel enlargement. • Over 90 % of urban channels show irregular response patterns to urbanisation. • Models must account for geology, sediment, hardpoints, and vegetation for accuracy. [ABSTRACT FROM AUTHOR]

Hydraulic balance within the heating system's pipeline network is essential for efficient operation. Hydraulic imbalances can result in increased energy consumption and heat loss. Accordingly, a new dynamic hydraulic model has been developed, leveraging the topological structure of the network. This model incorporates the nonlinear constraints associated with flow coupling between electric valves and variable frequency pumps, with the objective of minimizing energy used in pump operation. It determines the optimal pump frequency and valve settings for operational adjustments. The model's predictive accuracy was validated using real operational data from a campus heating system. Additionally, it calculates the campus's ideal load and evaluates the potential for energy savings. Three adjustment strategies were established based on different temporal scales: hourly, day-and-night, and daily. Findings indicate that the optimized system offers substantial energy savings, particularly the hourly adjustment, which reduces pump energy consumption by 38.2 % and total system flow by 9.0 %. The day-and-night variable frequency was the next most effective, reducing pump energy consumption by 32.8 %, and total system flow by 7.6 %. The daily variable frequency strategy showed the least energy savings, with pump energy consumption by 25.0 %, and total system flow by 5.5 %. This dynamic hydraulic regulation optimization model serves as a valuable tool for developing intelligent heating systems. • A new dynamic hydraulic model was developed based on the actual network topology. • The model considers nonlinear constraints between valves and pumps. • Three strategies were set based on different time scales. • Hourly adjustment achieves optimal energy savings, pump energy cut by 38.2 %. [ABSTRACT FROM AUTHOR]

In this paper we consider calibration of hydraulic models for district heating networks based on operational data. We extend previous theoretical work on the topic to handle real-world complications, namely unknown valve characteristics and hysteresis. We generate two datasets in the Smart Water Infrastructure Laboratory in Aalborg, Denmark, on which we evaluate the proposed procedure. In the first data set the system is controlled in such a way to excite all operational modes in terms of combinations of valve set-points. Here the best performing model predicted volume flow rates within roughly 5 and 10 % deviation from the mean volume flow rate for the consumer with the highest and lowest mean volume flow rates respectively. This performance was met in the majority of the operational region. In the second data set, the system was controlled in order to mimic real load curves. The model trained on this data set performed similarly well when evaluated on data in the operational range represented in the training data. However, the model performance deteriorated when evaluated on data which was not represented in the training data. • We perform data-based parameter tuning for hydraulic district heating models. • We utilize measurements from only a few sensors. • We parameterize valves with hysteresis and unknown characteristics. • Two experimental data-sets are created to test the proposed methodology. • The data-sets are open and available for further studies. [ABSTRACT FROM AUTHOR]

In this study, we developed a new general approach to estimate the macroscopic capillary length (λ c) using different hydraulic function models and related shape parameters, along with the Haverkamp infiltration model constant. We next applied this new approach to the van Genuchten model coupled with a Burdine condition (vGB) to estimate λ c. Then, we applied the new λ c computation to three different methods for estimating saturated hydraulic conductivity (K s), and analyzed two sets of constant infiltration data: 1) an analytically generated Beerkan-type dataset and 2) constant head and Beerkan-type infiltration tests performed at the Ambarköprü Experimental Station of Blacksea Agricultural Research Institute in Samsun, Turkey. Our new approach provided accurate K s estimates when applied to the analytical Beerkan infiltration data. The highest error was observed for a silt soil, with 30 % error for one formulation versus <15 % for the others. For synthetic coarse-textured soils such loamy sand and sandy loam, the error was <10 %. For the field data and Beerkan-type experiments, the new approach gave consistent estimates of K s regardless of analytical interpretation. However, ANOVA analysis revealed that K s varied between different infiltration test types, with constant head infiltrometry with 5 cm of applied water head having greater K s values than the Beerkan tests (p < 0.05). Estimated K s values also differed between land use types (p < 0.01), with a maize field having significantly greater K s compared to a soybean field. Overall, we conclude that the proposed approach represents an efficient and appropriate method for characterizing point-scale saturated hydraulic conductivity, so long as experimental artifacts such as ring insertion deep and preferential flows are considered. • A generalized formulation for macroscopic capillary length (λ c) using Haverkamp model is proposed. • λ c is successfully validated using Beerkan infiltration analytical data. • In the field, K s estimations were significantly different between Beerkan and constant head infiltrometry. • Caution is advised when using the formulation for positive constant head infiltrometry [ABSTRACT FROM AUTHOR]

Miniature switching valve internal flow pattern is relatively complex, in the working process of the hydraulic valve cavity often produces low-pressure areas, and eddy currents, as well as leads to spool deformation and displacement of the hydrodynamic force and other phenomena. This affects the stability of the internal flow field of the hydraulic valve, especially when the hydraulic pressure is too large to block the spool movement, inaccurate action is present, or even spool opening and closing failure is jitter out of control. Other phenomena, this paper designs a new type of spool and body combination of miniature switching hydraulic valves, to reduce its axial hydraulic pressure. Firstly, a three-dimensional model of the hydraulic valve with different seat angles was established; secondly, CFD numerical analysis of the model was carried out using FLUENT, and the axial steady state hydrodynamic force was studied by comparing the simulation results. The results show that by simultaneously modifying the geometry of the spool and the valve body, the axial component of the hydrodynamic force can be significantly reduced, thus significantly changing the magnitude of the axial hydrodynamic force of the switching valve, to satisfy the requirement of reducing the driving force required for the work, and to achieve the reduction of power consumption. Finally through the hydraulic valve comprehensive test bench to verify the accuracy of the miniature switching valve, through the research of this paper, can provide a certain reference for the design and research of the switching valve. • The original structure is optimized and the flow field in the inner cavity of the valve body is simulated using FLUENT. • The effect of the optimized miniature switching valve in terms of axial steady state hydrodynamics was investigated. • Analyzed each set of simulation results and experimental verification, and came up with a relatively optimal structure. [ABSTRACT FROM AUTHOR]

To solve the problem of cracks in the secondary lining of the Yanglin Tunnel caused by the creep of water-rich surrounding rock, this study established a rock creep model of hydraulic interaction based on rock creep theory, fractional calculus theory, damage mechanics theory, and effective stress principle. Based on the secondary development module of the numerical computation software, a rock creep model of hydraulic interaction was embedded in the software to verify the model. In addition, a new support scheme was developed using the convergence-confinement and orthogonal experimental methods. Furthermore, a newly developed rock creep model was used to conduct a numerical simulation analysis of the new support scheme for the cracked section of the secondary lining of the Yanglin Tunnel under hydraulic interaction, verifying the long-term stability of the new support. The results were as follows. (1) Under hydraulic interaction, the established rock creep model effectively simulated the creep calculation process of standard rock samples, and the numerical calculation results were consistent with the experimental results. (2) The new support scheme significantly controlled the displacement changes in the surrounding rock and significantly reduced the growth rate of the crown displacement and clearance convergence. The final numerical calculation results converged and the displacement stabilized, indicating that the new support scheme had an ideal controlling effect on the displacement of the surrounding rock. (3) A numerical simulation analysis was conducted to optimize the support for the cracked section of the tunnel lining using a developed rock creep model under hydraulic interaction. The calculation results aligned with the actual engineering requirements, indicating that the rock creep model under the hydraulic interaction of secondary development can effectively simulate the creep calculation process of tunnel construction, thereby reflecting the validity and accuracy of the program. The proposed support scheme was applied to the reconstruction of a cracked section of the secondary lining of the Yanglin Tunnel. [ABSTRACT FROM AUTHOR]

The aim of this study was to simulate the water flow and reactive transport of pollutants in a horizontal flow (HF) wetland to better understand the recovery time of the treatment performance for peak load events. For the simulation, the processes-based model HYDRUS and its Wetland Module is used. The system under investigation is the first stage of the 9-years old hybrid treatment wetland of a large retail store, located in Catania, Italy. For the calibration of the hydraulic model, the data of a tracer test was used. The data set of the systems is available for a seven year period including organic matter and ammonia nitrogen. The data was split into a standard event representing low loading conditions and determined peak load events with high loadings. The results show that the response time of the model correlates with the hydraulic retention time from the tracer experiment and indicates that higher peak load concentrations at the inlet of the system lead to a longer recovery time of the wetland. • Positive correlation found between influent peak and corresponding recovery time. • High influent COD delays outlet quasi-steady-state condition. • Peak load events simulation in short timeframe need standard conditions application. • Importance of considering peak load scenarios during TW design and management. [ABSTRACT FROM AUTHOR]

Satellite altimetry data has become essential for studying the dynamics of water bodies, especially in regions with limited or inaccessible data. Traditional low-resolution mode (LRM) satellites' accuracy cannot be guaranteed when it comes to assessing water levels in small- (< 200 m in width) and medium-sized (200–800 m in width) rivers. Synthetic aperture radar (SAR) altimeters, exemplified by Sentinel-3 A, have shown great potential for inland water altimetry. Nevertheless, developing algorithms to retrack the raw data remains an essential requirement in this context. This is attributed to the width of small-sized rivers, which is often narrower than the along-track resolution of both LRM and SAR altimeters. In addition, new altimeters may have long revisit cycles and different spatial coverage and cannot yield historical data necessary in some situations. To address these challenges, this study proposed a conditional threshold retracker (CTR). The CTR algorithm is well-designed and facilitates accurate water level monitoring. Moreover, we proposed an enhanced footprint filter (EFF), thus significantly bolstering the number of available cycles. Our findings demonstrate that the developed method substantially enhances the temporal and spatial resolution of both LRM and SAR altimetry satellites during water level monitoring in rivers of different climate types. The width of the thirteen selected rivers is on the order of 85–630 m. The CTR significantly improved the water level monitoring accuracy by 68 %–78 %. Furthermore, the EFF increased the number of water level cycles by approximately 49 %–68 %. These findings have practical implications for obtaining accurate water level data, estimating river discharge and improving hydraulic model calibration. • An improved methodology (CTR and EFF) retrieves accurate water levels. • The proposed algorithm is more accurate than other retrackers in narrow rivers. • The CTR and EFF are applicable to both LRM and SAR altimetry satellites. [ABSTRACT FROM AUTHOR]

In this study, we present a thermodynamically consistent thermo-fluid–solid–elastic–plastic phase-field model to accurately capture the propagation process of hydraulic fracture in deep shale. The developed model takes into account the degradation of the thermoelastic–plastic parameters, strain hardening, mixed-mode fracture, and thermal convection. The model incorporates an uncorrelated Drucker–Prager constitutive model with a nonlinear saturated strain function to capture the deformation behavior of shale. The driving force of the fracture integrates the effects of elastic, plastic dissipative, fluid, and thermal energies of the rock. The model is constructed in a numerical computation iteration format using finite element discretization and Newton–Raphson iteration. To solve the coupled problem more efficiently, a staggered iteration algorithm is adopted to solve the displacement, pressure, temperature, and phase fields. Several numerical results are extracted and compared with the analytical solution results and experimental test data to demonstrate the accuracy and validity of the proposed model. In addition, the propagation behavior of hydraulic fractures in thermoelastic–plastic reservoirs with homogeneous, natural fractures or layering is investigated, and the results show that the model can capture complex fracture propagation patterns. [Display omitted] • A new thermo-fluid–solid–elastic–plastic phase-field model is presented. • The driving force integrates the effects of elasticity, plastic dissipation, fluid, and thermal energy. • A new mixed fracture model is proposed. • The model is validated using an analytical solution model and experimental test results. • The model satisfies thermodynamic consistency. [ABSTRACT FROM AUTHOR]

This paper is devoted to constructing a dynamic numerical model for the firing dispersion caused by the autocannon dynamic characteristics. The buffer dynamics and projectile-barrel coupling are considered. First, the simulation of autocannon firing dispersion using commercial software usually leads to expensive computational costs. Second, autocannon dynamic design includes multiple subsystem models with nonlinearities. The conventional design method makes it difficult to describe the dynamic response of such complex systems with a unified model. To end these, a dynamic junction bond space method is proposed for analyzing muzzle vibration and firing dispersion under continuous firing loads, where the gene expression programming (GEP) method is adopted to construct the surrogate model for the buffer flow field. For the coupling analysis of the projectile and barrel, the projectile load is applied at a moving junction, which coincides with the flexible node of the barrel. By this, the dynamic numerical model for autocannon firing dispersion is established, and then the system state equation is obtained for each time step. Moreover, an autocannon standing target shooting example is presented to demonstrate the validity of the proposed method; the results show that the firing dispersion from the bond space model is consistent with the test. • Bond space model containing moving 1-junction characterizes autocannon firing process. • Embedding surrogate model of buffer hydraulic resistance simplifies the complexity of the dynamic model. • Digital prototype contains the structure information required for dynamic design. • Predicting autocannon firing dispersion through dynamic modeling. [ABSTRACT FROM AUTHOR]

Reliable estimates of low flow and flood discharge at ungaged locations are required for evaluating stream flow alteration, designing culverts and stream crossings, and interpreting regional surveys of habitat and biotic condition. Very few stream gaging stations are located on small, remote streams, which typically have complex channel morphology. Adequate gaging is also lacking on larger streams that are remote, smaller than those typically gaged, or have channel morphology not conducive to installation of gages. Complex channels typically contain large scale hydraulic roughness elements that dominate flow patterns (i.e., form roughness), making it difficult to measure channel cross-section area and water velocity, or to measure channel volume even where discharge is known. In channels with large channel form roughness, it is equally difficult to estimate discharge using commonly applied equations based on slope and channel dimensions or basin area. We employed a novel approach that explicitly accounts for hydraulic resistance from large wood and riffle-pool morphology (form roughness) in calculating low flow and bankfull discharge from stream and river physical habitat data collected from 4229 stream and river sites in the conterminous US (CONUS) sampled in 2008–9 and 2013–14 as part of the US Environmental Protection Agency's N ational R ivers and S treams A ssessment (NRSA). Hydraulic resistance derived from form roughness clearly dominated resistance derived from bed particles (particle resistance) during summer low flows in wadeable streams across the spectrum of channel slopes and substrate sizes smaller than boulders. Under bankfull conditions, the influence of form resistance relative to particle resistance was diminished, but form resistance still dominated except in large low gradient rivers lacking complex channels, and in streams or rivers with boulder-size bed particles. We validated our hydraulic resistance estimates by comparing measured discharges with calculated discharges that used those hydraulic resistance estimates along with measured NRSA channel morphology data. Morphology-based summer discharge (low flow) estimates and direct field measurements of discharge in 2333 wadeable CONUS streams showed reasonable agreement (median difference < 2.5×) for discharges ranging from 3.6 × 10−5 to 123 m3/s and drainage areas of 0.12 to 171,000 km2. In a subset of 759 of NRSA's larger wadeable stream and non-wadeable river sites where nearby U.S. Geological Survey (USGS) gage data were available and adequate, our morphology-based summer discharge estimates agreed fairly well (median difference < 2.0×) with USGS 20-yr average August mean flows ranging from 0.003 to 16,000 m3/s. Similarly, morphology-based estimates of bankfull flow ranging from 0.3 to 100,000 m3/s agreed reasonably well with the 1.5-yr recurrence interval flood in these gaged sites (median deviation <2.2×). These findings demonstrate the importance of quantifying flow resistance from large-scale form roughness features in natural channels and provide a novel approach for estimating discharge from widely available survey data. This will allow examination of discharge and its ecological influence across the full range of stream and river sizes sampled by NRSA or other synoptic surveys where comprehensive measures of biota, physical habitat, and chemistry are also made. Although these morphology-based estimates exhibit some variability, they are adequate for examining regional patterns in discharge and flow alteration and their association with instream biota and anthropogenic disturbances, providing summer low and bankfull flow information where reliable estimates are lacking. [Display omitted] • Flow information lacking for small and medium sized streams and in remote areas. • Large-scale roughness dominates hydraulic resistance in most US rivers and streams. • Form roughness essential for estimating discharge based on channel morphology. • Our morphology-based estimates (Q calc) incorporate large-scale form roughness. • Q calc agreed well with flow measurements and gages: 50 % of deviations <2–2.5 fold. • Q calc reliable where hydrologic models (e.g., NHDPlus) are not. [ABSTRACT FROM AUTHOR]

The article presents a method of solving a research and technological problem related to the optimization of data transmission and stabilization of interactions between the components of the information and communication technologies and hardware systems managing the process of predictive diagnostics of machines and devices as well as inferential control of actuators of the critical water supply network infrastructure. Building an intelligent infrastructure of the water production and distribution system requires the use of highly efficient IT systems that enable complex computational processes, including a dynamic hydraulic model of the network, as well as simulation of changes in process and technological parameters in real time. The conducted analyses have shown that the optimal approach is to combine virtual solutions with solutions based on physical workstations. An important consideration was to adjust system to the requirements of the Cybersecurity Act along with the selection of appropriate equipment enabling the implementation of procedures ensuring network security and safe access to the resources of the intelligent water supply system. [ABSTRACT FROM AUTHOR]

This paper proposes a nonlinear predictive generalized minimum variance (NPGMV) control scheme for automatic control of the managed pressure drilling (MPD) systems in the presence of disturbances. Since the exact model of the system is not usually available in practice, the hydraulic flow model of MPD is described by an autoregressive second-order Volterra model. The conventional least-squares method is applied to input–output data, thereby identifying the Volterra model. Bottom-hole pressure regulation and kick handling are achieved through the control scheme. To deal with a reservoir kick, the proposed method switches to flow control mode automatically, and prevents the reservoir fluid influx into the well surface. The proposed method also has the capability to keep the bottom-hole pressure above the reservoir pressure during a formidable scenario such as pipe connection. In addition, the robustness of the controller in the face of heave disturbance and uncertainty is investigated. To show the effectiveness of the proposed method, the comparison study of several scenarios with a switching PI controller is provided and demonstrates the NPGMV control outperforms other approaches with respect to steady-state performance. • A nonlinear predictive generalized minimum variance (NPGMV) control is proposed for managed pressure drilling (MPD) systems in the presence of disturbances. • Representing the hydraulic flow model of the MPD system by exploiting an autoregressive second-order Volterra series model. • To deal with a reservoir kick, a switching control solution is provided. • Robustness of the proposed control scheme is evaluated in face of heave disturbance and model uncertainty. • Using the conventional least-squares method to identify an inputoutput model without the need for having an exact model of the system. [ABSTRACT FROM AUTHOR]

The structure of the hydraulic drifter is introduced, and the process of drilling into rocks by the drifter is established as a physical model of rock with three-degree-of-freedom dry friction. Four modes of the physical model are introduced. The solutions of the physical model are divided into three segments. The angular frequency and amplitude of the hydraulic force are taken as control parameters to obtain stable periodic trajectories and the point of maximum R O P. Bifurcations such as period-doubling, saddle–node, and torus are discovered. The data acquisition system for drilling rocks with a hydraulic drifter is introduced, and the displacement and velocity of the piston obtained from the model and experiments are compared. The results indicate that to make the drifter work on the non-stick penetration mode of period-1, the range of angular frequency should be 2. 66 < ω < 5. 28 , and the range of amplitude should be 0. 13 < a < 3. There is a strong correlation between the experiments and the model, and compared to the experiment, the piston in the model undergoes deceleration before colliding with the drill string, adding an impact deceleration stroke. [ABSTRACT FROM AUTHOR]

This paper proposes a force controller for hydraulic actuators of the valve-manipulated type. The structure of the proposed controller is similar to that of the admittance controllers used for robotic systems, incorporating a virtual mass–damper system that transforms the measured force to the reference velocity. In the proposed controller, the reference velocity is transformed into the valve opening commands through a quasi-static hydraulic actuator model. This paper also proposes an energy-based stabilizer that imposes limits on the reference velocity to prevent the instability induced by the deadtime, which commonly exists in hydraulic systems. The proposed controller, combined with the stabilizer, is validated with a laboratory setup composed of a linear hydraulic actuator that makes contact with a stiff external environment. [ABSTRACT FROM AUTHOR]

The hydromechanical characteristics of unsaturated loess determine the engineering performance such as bearing capacity and stability of compacted loess structures. In this study, the volume change equation is constructed in the effective stress-saturation space by correlating soil compressibility with saturation. Meanwhile, a hydraulic model considering the influence of volumetric strain is introduced to develop a hydraulic-mechanical elastoplastic model for unsaturated loess. Furthermore, a stress ratio sensitivity parameter is developed to describe the initial structural strength attenuation of unsaturated loess under loading, introducing the sensitivity parameter to modified effective stress to characterize the hydromechanical behaviors under initial structural strength attenuation. The proposed model can well describe the coupling effect of hydraulic and mechanical wetting. Using the constraints of the saturation and volumetric strain relationship under undrained conditions, predictions of soil–water change are achieved via net stress and deviatoric stress driving. And then the excellent performance of the proposed model in predicting the hydromechanical behavior of unsaturated compressed loess under undrained conditions is verified. [ABSTRACT FROM AUTHOR]

Riverine barriers are threatening freshwater fish migration, with major impacts on fish populations. Effective management requires understanding of fish movement and behaviour as they approach a barrier and fish pass, which can inform optimal mitigation options and barrier management. Here, the movements of upstream migrating barbel Barbus barbus and grayling Thymallus thymallus near a barrier were analysed and results used to develop predictive models. Fish were tracked via 2D acoustic telemetry. Hidden Markov models were used to distinguish behavioural states and step selection functions were applied to determine habitat selection by the fish in each state. Model results were explored to assess the benefits of including behavioural state and understand state-specific habitat preferences, then cross-validated and used to develop an individual based model to predict fish spatial usage. Little difference existed in habitat selection between states and individual variation was high, limiting general trends that could be described. Overall, barbel preferred deeper or faster water while for grayling, few trends could be described. Under the tested flow conditions, high spatial usage was predicted in the area directly downstream of the barrier. In addition, barbel usage was high in the area by and downstream of the fish pass entrance but not for grayling, which may indicate a need to improve pass attractiveness for grayling. The predictive model produced directed upstream movements of fish similar to those expected for upstream migrating freshwater fish, highlighting model potential for fish passage applications in future iterations. The high individual variability in fish behaviour drives the need for individual-based approaches for predicting fish movement. [Display omitted] • Effective mitigation of riverine barriers relies on understanding patterns behind fish movement near a barrier. • Thirty-one freshwater fish were tracked during their upstream spawning migration in the downstream area of a barrier. • Behavioural-state specific habitat selection was analysed and used to predict spatial usage. • Habitat selection differed little between behavioural states but varied greatly among individuals. • Combining acoustic telemetry and hydraulic models is a powerful avenue to understand and predict fish spatial usage. [ABSTRACT FROM AUTHOR]

The workover riser system undergoes severe axial response after an emergency disconnection, which can easily lead to accidents. However, research on recoil control for the workover riser system is lacking. The recoil dynamic model of workover riser system is established, including split tensioner system model based on hydraulic dynamics and workover riser model based on finite element method. Considering the nonlinearity of workover riser system and the complexity of operating environment, fuzzy controller and ACO-Fuzzy controller are designed to address the recoil control of the workover riser system. The control effect of fuzzy controller and ACO-Fuzzy controller is analyzed and compared. The results indicate that both fuzzy controller and ACO-Fuzzy controller can realize recoil control. The ACO-Fuzzy controller has superior control effect on the recoil process of the workover riser system compared to the fuzzy controller. Additionally, ACO-Fuzzy controller has better adaptability than fuzzy controller when the water depth and tension ratio change. • A nonlinear recoil model considering the coupling effect of split tensioner system and workover riser is established. • A fuzzy controller and an ACO-Fuzzy controller are designed for workover riser recoil control. • The ACO-Fuzzy controller has better control effect and adaptability compared to fuzzy controller. [ABSTRACT FROM AUTHOR]

Hydraulic suction collection has been extensively utilized in deep-sea mining due to its high flow rate and efficiency. This paper introduces a novel hydraulic collection model to investigate the impact of various collection parameters on collection efficiency. We analyze the effect of different ore collection parameters on collection efficiency using a radial basis function network and make predictions. The optimal parameter range was obtained by performing combined parameter experiments. The two-parameter combination give better results compared to a single parameter. A theoretical model of collection efficiency is established based on experimental observations and principles of water jet theory. The accuracy of the model is confirmed through experimental validation, and the research findings can provide valuable insights for the ore collection process in deep-sea mining. • The influence of three parameters were analyzed using RBFN and an order of importance was obtained. • The three parameters were analyzed in combinations of two to determine optimal ranges. • The actual process was simplified into a theoretical model and formula derivation has been conducted. [ABSTRACT FROM AUTHOR]

Understanding and mitigating wave overtopping are crucial for hinterland safety, yet research primarily focuses on designing coastal structures, with limited attention to structural materials. As global warming intensifies coastal hazards, there is a growing need for resilient infrastructures. A hybrid infrastructure incorporating vegetation alongside concrete may offer a viable solution. In this study, we evaluated the effect of vegetation on wave overtopping reduction under strong winds through hydraulic model experiments simulating extreme storm conditions. The experiments were conducted under the simultaneous action of wind, waves, and vegetation using a two-dimensional wind tunnel flume and vegetation. A higher vegetation density was found to exponentially reduce the overtopping rate. Moreover, dense vegetation was demonstrated to be equivalent to raising the height of protective structures by at least 1.1 m. Furthermore, the increase in overtopping rate by the effects of wind can be compensated by the reduction effects of vegetation. Based on these investigations, an equation was proposed to predict the wave overtopping rate that considers the effects of both wind and vegetation. The results highlight the potential applicability of vegetated coastal protection in future coastal disaster prevention against extreme events with stronger winds and waves that may be induced by climate change. • Wave overtopping rate exponentially decreased as the vegetation density increased. • Dense vegetation was equivalent to raising the dimensionless freeboard by 1.1 m. • Vegetation can decrease the wave overtopping rate increased by wind flow. • An equation was proposed to predict wave overtopping considering wind and vegetation. [ABSTRACT FROM AUTHOR]

• Large real-time water distribution systems require accelerated hydraulic calculations. • Deep-level decomposition and parallel computation are used to gain acceleration. • Time savings of more than 50 % can be gained in large water distribution network model. • The size and structure of decomposed model affect the potential time savings. As the size of water distribution network (WDN) models continues to grow, developing and applying real-time models or digital twins to simulate hydraulic behaviors in large-scale WDNs is becoming increasingly challenging. The long response time incurred when performing multiple hydraulic simulations in large-scale WDNs can no longer meet the current requirements for the efficient and real-time application of WDN models. To address this issue, there is a rising interest in accelerating hydraulic calculations in WDN models by integrating new model structures with abundant computational resources and mature parallel computing frameworks. This paper presents a novel and efficient framework for steady-state hydraulic calculations, comprising a joint topology-calculation decomposition method that decomposes the hydraulic calculation process and a high-performance decomposed gradient algorithm that integrates with parallel computation. Tests in four WDNs of different sizes with 8 to 85,118 nodes demonstrate that the framework maintains high calculation accuracy consistent with EPANET and can reduce calculation time by up to 51.93 % compared to EPANET in the largest WDN model. Further investigation found that factors affecting the acceleration include the decomposition level, consistency of sub-model sizes and sub-model structures. The framework aims to help develop rapid-responding models for large-scale WDNs and improve their efficiency in integrating multiple application algorithms, thereby supporting the water supply industry in achieving more adaptive and intelligent management of large-scale WDNs. [Display omitted] [ABSTRACT FROM AUTHOR]

• A rate-dependent cohesive phase-field model for dynamic quasibrittle fracture is developed. • Dynamic changes in the poroelastic parameters with phase-field evolution are considered. • Poiseuille flow in fractures is modeled by deformation-dependent permeability. • The proposed model is validated by an analytical solution, a benchmark test and numerical examples. A novel rate-dependent cohesive phase-field model that can simulate fluid-driven dynamic quasibrittle fracture in soft coal rocks is presented. The coal matrix and fractures are described by a unified fluid continuity equation, and the Poiseuille flow in the fractures is modeled by deformation-dependent permeability. Dynamic evolution equations for porosity, permeability and the Biot coefficient during phase-field evolution are developed. The phase-field evolution equation is derived from the total energy generalization based on the Francfort–Marigo variational principle. To simulate the rate-dependent dynamic fracture problem accurately, the effects of the phase-field evolution dissipation energy and inertia energy are considered. The above multifield coupled system is solved via a staggered approach within the finite element framework via the Newton–Raphson iterative algorithm. The independence and convergence of the proposed model were verified, and its accuracy was validated via an analytical solution for crack width and a benchmark test for dynamic crack propagation. The propagation law of single/multicluster hydraulic fractures in coal seams with interlayers was investigated via the proposed model. The simulations revealed that the number of clusters and the mechanical properties of the interlayers significantly influence the fracture morphology. Finally, hydraulic fracturing of fracture-developed coal seams was simulated, confirming the potential of the proposed model. [Display omitted] [ABSTRACT FROM AUTHOR]

Leaks in district heating networks result in waste of water and heat, and even threaten personal safety. Various machine learning-based methods have been proposed to realize leak localization and gain satisfying performance based on a large amount of leak samples. However, the creation of such samples demands a substantial investment of time and computational resources, presenting challenges for real-time applications. Previous studies have rarely addressed the influence of leak dataset construction and efficient creation methods. To fill this limited area, this paper conducts a comparative analysis on the variables in leak dataset and proposes an effective method for sample dataset generation, complemented by a novel accuracy evaluation that incorporates the topological relationship among pipelines. A multi-source looped heating network is employed to do the case study. The results demonstrate that the proposed method achieves satisfactory leak localization performance with a significantly reduced training set. Furthermore, by segmenting the physical pipeline into multiple virtual pipelines and using the adjacent evaluation metric, the leak localization method achieves a 75 m error with an accuracy of 0.998. • A novel hydraulic model is introduced considering leakage on pipeline. • A dataset size reduction method is proposed to improve efficiency. • A new evaluation method is proposed to reduce the physical distance error. [ABSTRACT FROM AUTHOR]

Accurately determining the hydraulic conductivity of unsaturated bentonite is important for modeling subsurface thermo-hydro-mechanical and chemical processes. This study introduced a new hybrid model that employs a constrained categorial boosting (CatBoost) algorithm, combined with a genetic algorithm for hyperparameter tuning, to estimate the hydraulic conductivity of unsaturated compacted bentonite The performance of the constrained CatBoost model was benchmarked against a diverse set of data-driven baseline regression models, including lasso, elastic net, polynomial, k-nearest neighbors, decision tree, bagging tree, random forest, and CatBoost. The results indicated that the constrained CatBoost model offers a superior balance between model robustness and predictive accuracy in estimating the hydraulic conductivity of compacted bentonite-based materials during the wetting phase. The model effectively captured the U-shape relationship between hydraulic conductivity and suction, a key characteristic of bentonite behavior. Additionally, bootstrapping analyses confirmed the model's reliability under data variability, further validating its applicability in environmental and geotechnical applications. • Developed a constrained CatBoost model for hydraulic conductivity of compacted bentonite. • The model demonstrated higher accuracy and robustness compared to traditional data-driven models. • The model captured the U-shaped relationship between hydraulic conductivity and suction. [ABSTRACT FROM AUTHOR]

This contribution presents a novel approach for the calibration of distributed parameters in a 2D urban flood hydraulic model. It focuses on the challenging issue of inferring distributed friction parameters from multi-source heterogeneous spatio-temporal observations of their hydraulic signatures in the context of an urban flash flood in a complex street network. A variational data assimilation algorithm is used to infer high-dimensional multi-variate parameters (spatialized friction and inflow discharge time series) using multi-source observations. This method relies on a differentiable 2D shallow water hydraulic model which enables to generate high-resolution sensitivity maps of local gradients and Derivative-based Global Sensitivity Measures (DGSM), enabling to guide adequate definition of parameter spatialization for the data assimilation process. Assimilated data include real local limnigraphic measurements and high-water marks collected after a major flood event, as well as modeled flow velocity used in twin experiments setups. This study is the first to leverage high-water marks with a variational method for the calibration of distributed parameters in an urban flood model. The multi-source data is used to infer inflow hydrographs and distributed friction parameters in setups of varying complexity. In the main setup, the complex structure of the street network, along with the sensitivity maps and hydraulics expertise led to define a model configuration with 45 friction patches. A high-dimensional parameter vector composed of these friction values and an upstream inflow is inferred simultaneously by assimilating real limnigraphic data and high-water marks. This leads to an increase in model fit to observations and satisfying parameter estimates. • A VDA method is applied to a 2D urban hydraulic model to infer distributed parameters. • Gradient-based high-resolution sensitivity patterns are mapped with adjoint code. • Multi-source data are assimilated to infer multivariate high-dimensional controls. • Assimilation of high-water marks provides distributed information on model response. • Inferences improve fit to observation given appropriate model controllability. [ABSTRACT FROM AUTHOR]

Fractures control fluid flow, solute transport, and mechanical deformation in crystalline media. They can be modeled numerically either explicitly or implicitly via an equivalent continuum. The implicit framework implies lower computational cost and complexity. However, upscaling heterogeneous fracture properties for its implicit representation as an equivalent fracture layer remains an open question. In this study, we propose an approach, the Equivalent Fracture Layer (EFL), for the implicit representation of fractures surrounded by low-permeability rock matrix to accurately simulate hydromechanical coupled processes. The approach assimilates fractures as equivalent continua with a manageable scale (≫1 μm) that facilitates spatial discretization, even for large-scale models including multiple fractures. Simulation results demonstrate that a relatively thick equivalent continuum layer (in the order of cm) can represent a fracture (with aperture in the order of μm) and accurately reproduce the hydromechanical behavior (i.e., fluid flow and deformation/stress behavior). There is an upper bound restriction due to the Young's modulus because the equivalent fracture layer should have a lower Young's modulus than that of the surrounding matrix. To validate the approach, we model a hydraulic stimulation carried out at the Bedretto Underground Laboratory for Geosciences and Geoenergies in Switzerland by comparing numerical results against measured data. The method further improves the ability and simplicity of continuum methods to represent fractures in fractured media. • We propose a representation method to model fractures as an equivalent continuum medium. • The method can reproduce accurately the HM response of a single fracture. • The method is validated with a field-injection experiment at the Bedretto site. [ABSTRACT FROM AUTHOR]

Hydraulic conductivity exhibits a high spatial variability due to the heterogeneity and discontinuity of the geologic environments and their constituent materials. Representing such variability is problematic when implementing groundwater flow models, especially in geological media such as fractured rocks, fractured porous media, and karstic media, where the scale of observation is important when defining the heterogeneity of the media. In those cases, hydraulic tests performed locally in the fractures measure hydraulic conductivity at a fine scale. Nevertheless, groundwater flow models usually deal with problems involving a regional scale, with a grid cell size much greater than the cell in the fine scale. Modeling groundwater flow in fractured media using the Discrete Fracture Network (DFN) method at the regional scale is still challenging due to the difficulty of hydraulically characterizing the entire fracture network using the limited available data. Instead, methods such as Equivalent Porous Media (EPM) represent the fractured media as a continuous media, making it more practical to represent fractured rocks as a continuous equivalent media in regional models than the DFN method. However, in approaches such as EPM, choosing the block size adequately is critical because, at large scales, it can considerably affect the simulated flow patterns. Accordingly, upscaling hydraulic conductivities of fracture networks at the fine scale into equivalent parameters at the scale of the model's block is still a relevant question in practical groundwater modeling. This paper reviews the most widely used hydraulic conductivity scaling techniques to identify methods that consistently represent fractured media groundwater flow dynamics in regional models. [ABSTRACT FROM AUTHOR]

Operators of water distribution systems (WDSs) need continuous and timely information on pressures and flows to ensure smooth operation and respond quickly to unexpected events. While hydraulic models provide reasonable estimates of pressures and flows in WDSs, updating model predictions with real-time sensor data provides clearer insights into true system behavior and enables more effective real-time response. Despite the growing prevalence of distributed sensing within WDSs, standard hydraulic modeling software like EPANET do not support synchronous data assimilation. This study presents a new method for state estimation in WDSs that combines a fully physically-based model of WDS hydraulics with an Extended Kalman Filter (EKF) to estimate system flows and heads based on sparse sensor measurements. To perform state estimation via EKF, a state-space model of the hydraulic system is first formulated based on the 1-D Saint-Venant equations of conservation of mass and momentum. Results demonstrate that the proposed model closely matches steady-state extended-period models simulated using EPANET. Next, through a holdout analysis it is found that fusing sensor data with EKF produces flow and head estimates that closely match ground truth flows and heads at unmonitored locations, indicating that state estimation successfully infers internal hydraulic states from sparse sensor measurements. These findings pave the way towards real-time operational models of WDSs that will enable online detection and mitigation of hazards like pipe leaks, main bursts, and hydraulic transients. • New hydraulic solver enables state estimation in large water distribution networks. • State estimation via EKF improves estimates of hydraulic heads at ungaged sites. • Methodology will enable real-time observability and improve detection of hazards. [ABSTRACT FROM AUTHOR]

• Surrogate models are developed for flow routing of urban drainage networks. • Graph neural networks are more cost-effective than fully-connected ones. • Physics-guided mechanisms are incorporated to restrict model predictions. • The models accelerate hydraulic predictions for real-time use. Physics-based models are computationally time-consuming and infeasible for real-time scenarios of urban drainage networks, and a surrogate model is needed to accelerate the online predictive modelling. Fully-connected neural networks (NNs) are potential surrogate models, but may suffer from low interpretability and efficiency in fitting complex targets. Owing to the state-of-the-art modelling power of graph neural networks (GNNs) and their match with urban drainage networks in the graph structure, this work proposes a GNN-based surrogate of the flow routing model for the hydraulic prediction problem of drainage networks, which regards recent hydraulic states as initial conditions, and future runoff and control policy as boundary conditions. To incorporate hydraulic constraints and physical relationships into drainage modelling, physics-guided mechanisms are designed on top of the surrogate model to restrict the prediction variables with flow balance and flooding occurrence constraints. According to case results in a stormwater network, the GNN-based model is more cost-effective with better hydraulic prediction accuracy than the NN-based model after equal training epochs, and the designed mechanisms further limit prediction errors with interpretable domain knowledge. As the model structure adheres to the flow routing mechanisms and hydraulic constraints in urban drainage networks, it provides an interpretable and effective solution for data-driven surrogate modelling. Simultaneously, the surrogate model accelerates the predictive modelling of urban drainage networks for real-time use compared with the physics-based model. [Display omitted] [ABSTRACT FROM AUTHOR]

In many developing countries, intermittent water supply (IWS) systems are prevalent, resulting in limited access to water for consumers who do not have continuous 24/7 supply. Consumers are compelled to utilize private storage tanks to adapt to IWS conditions and overcome periods with no water access. While achieving greater water availability, the use of storage tanks exacerbates existing supply inequity. We propose a simulation–optimization approach that models consumers using a volume-driven demand technique to account for IWS consumer behavior, and employs a Bayesian optimization to determine the flow control valve schedule to improve local supply and global equity. The results demonstrate the existence of a hierarchy in supply in which consumers with favorable hydraulic conditions are able to fill their tanks any time supply is available, leaving consumers with less-favorable hydraulic conditions to fill their tanks only when an excess in supply exists. With limited control, only some global disparities can be offset. Additionally, intermittency in supply exacerbates the inequity and limits the efficacy of controls, reinforcing the importance of improving the continuity in supply. The proposed approach provides insights into the mechanisms behind inequitable supply in IWS systems, where further research is needed to maximize consumer welfare. • Augmenting CWS hydraulic model to IWS hydraulic model. • Analyzing misalignment between local incentives and global equity. • Optimizing flow control valve schedule to maximize equity in intermittent systems. [ABSTRACT FROM AUTHOR]

• Decentralizing reduces real-life network complexity, optimizing efficiency. • Advanced pressure step-test enhances decentralized modeling and calibration. • DBSCAN ensures precise data accuracy by effectively handling noise and outliers. • Bayesian optimization achieves effective network calibration even with limited data. • Power and modified orifice equations robustly detect existing nodal leaks. The expansion of cities escalates the demand on water utilities amid global water scarcity, making leakage management a critical challenge for water sector sustainability. On this subject, the study introduces an advanced practical approach for estimating nodal leakage through the calibration of decentralized networks using available data. The approach includes conducting a pressure step-test for data collection, employing the DBSCAN algorithm for outlier detection, and employing Bayesian optimization for effective calibration. Hydraulic leakage models, particularly the power and modified orifice equations, are innovatively applied to model and identify existing leaks at each network node through deep comparison. The computational analysis demonstrated efficiency and accuracy in overcoming vast computational complexity and time constraints, with the calibration of a real-life network resulting in a cumulative MSE of 0.892 and an average R² and NSE values near 0.98. Additionally, realistic leakage modeling revealed inaccuracies in the acknowledged connection between the modified orifice equation and the leakage power equation. This study also provides key insights for enhancing water loss management and conducting on-site inspections in an environmentally conscious manner, especially crucial for budget-constrained water utilities and authorities experiencing revenue declines. [ABSTRACT FROM AUTHOR]

The hydraulic power take-off (PTO) system of wave energy converter (WEC) is a key component of the floating wind-wave hybrid system. It has a notable influence not only on the overall power performance, but also on the motion response which represents wave stability and survivability. Its parameter analysis and optimization is essential, but is ignored in the previous studies. For this reason, this study established a fully-coupled mathematical model of the hybrid system with a complete hydraulic PTO system. Sensitive analysis of 6 hydraulic parameters on the power absorption and pitch motion of the hybrid system are conducted. A surrogate model based on elliptical basis functions neural network (EBFNN) is established to meet the computing needs. The optimization of hydraulic parameters is conducted by the NSGA-II multi-objective optimization algorithm with dual objectives: maximum power absorption and minimum pitch motion. The results show that 6 parameters has an interaction effect between each other. The throttle valve port flow area has the most significant effect on the power absorption, and the pre-charged volume of the accumulator has the most significant effect on the motion response. Four groups of optimal parameter values are recommended to provide reference for system design. • A fully coupled hybrid system model with complete hydraulic PTO system is presented. • The EBFNN-based surrogate model can be well matched with the simulation model. • Sensitivity analyses are performed on six hydraulic parameters of the hybrid system. • Hydraulic parameters are optimized using NSGA-II multi-objective algorithm. [ABSTRACT FROM AUTHOR]

Advanced pipeline leak detection and localization techniques are needed to reduce greenhouse gas emissions from hydrocarbon transportation pipelines. Developing effective leak detection and localization methods is challenging due to the spatiotemporal dynamics of process variables, the presence of process/measurement disturbances and constraints, and the limited measurement data. To address this issue, this manuscript proposes a novel moving horizon estimation design for pipeline leak detection, constrained estimation of leak size and location by using an infinite-dimensional pipeline hydraulic model. Based on the mass and momentum balance laws and the Cayley–Tustin time-discretization method, an infinite-dimensional discrete-time pipeline hydraulic model is proposed considering (unknown but bounded) disturbance and leak. By introducing a coordinate transformation, we decouple the leak size and location estimation problems. The implementable discrete-time moving horizon estimator and observer are designed for constrained leak size and location estimation. The effectiveness of the proposed designs is validated via simulation examples. • An infinite-dimensional discrete-time pipe leak model with disturbance is proposed. • A moving horizon estimator (MHE) is designed for constrained leak size estimation. • Discrete-time observer and MHE are designed for leak localization. • Numerical simulation studies are performed to verify the proposed methods. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive study on phase-field modelling in COMSOL MultiPhysics for simulating dynamic hydraulic fracturing in porous media based on Biot's poro-elasticity theory. The focus is on addressing the challenges associated with crack width estimation in this context. A new strain-based crack width formulation is proposed, offering improved accuracy in predicting fracture permeability and ease of implementation in numerical approaches. The model's capabilities are extended to consider dynamic crack propagation by incorporating the kinetic energy in the governing coupled hydro-mechanical-damage equations. The numerical implementations in COMSOL MultiPhysics are thoroughly explained, providing insights into the techniques used to solve the governing equations. Verification examples, including the benchmark KGD verification, are presented to demonstrate the model's capabilities in simulating hydraulic fractures in porous media and validate its accuracy and reliability. A final numerical example focusing on the dynamics of crack propagation in a gravity dam is simulated, allowing for a comprehensive examination of the model's performance. The proposed strain-based crack width formulation and consideration of dynamic crack propagation contribute to improved accuracy in predicting fracture permeability. [ABSTRACT FROM AUTHOR]

• Scaling laws are used to design a thermal hydraulic model of a liquid–metal reactor. • The experimental facility E-SCAPE is a 1/6-scale model of MYRRHA built at SCK CEN. • Pressure losses are obtained from isothermal operation in forced circulation. • Hot plug experiments use temperature as a tracer to obtain flow patterns. The validation of decay heat removal systems and the characterization of thermal hydraulic phenomena in the plena of the liquid metal-cooled, pool-type research reactor MYRRHA, under design at SCK CEN, the Belgian Nuclear Research Centre, is accomplished by experiments and numerical investigations. For this purpose, the E-SCAPE facility at SCK CEN is a thermal hydraulic 1/6-scale 3-D model of the primary system of MYRRHA, with an electrical core simulator, and cooled with Lead Bismuth Eutectic (LBE). Its scaling is based on the preservation of the overall system behavior and the reproduction of the major thermal hydraulic phenomena under decay heat removal conditions. Specific attention in the scaling approach is given to stratification phenomena in the upper plenum and the mixing effect associated with jets entering the plena. From steady-state isothermal operation in forced circulation, experimental information is obtained on the pressure losses in the system. The relation between the pressure loss in the core and above core structure, and the level difference between the lower and upper plenum is confirmed. From hot plug experiments, using temperature as a flow tracer, a large amount of information on the flow patterns in forced circulation mode is generated. For instance, a clear difference can be observed in the behavior of pump jets entering the lower plenum between the high and low flow rate cases. One can also see that the LBE that exits the core, is going upwards through the above core structure before distributing radially in the uppermost fluid layers. From these layers, the fluid goes downward in the upper plenum towards the inlet windows of the heat exchangers. [ABSTRACT FROM AUTHOR]