Hydraulic Simulation Research Articles

Reliability of earthquake-size distribution and stress regime relationships for fluid-injection-induced seismicity

Induced seismicity caused by fluid injection associated with unconventional gas and geothermal projects, poses a significant hazard that requires effective mitigation and management. This issue is of concern to local and indigenous communities, regulatory bodies, operators and their insurers, as it poses risks to health, safety, and project economics and success. To assess the likelihood and potential magnitude (i.e., severity) of fluid-injection-induced seismicity events, empirical relationships for natural earthquakes have been co-opted that relate event size distributions (b-value) to focal mechanisms and inferred in-situ stress regimes. However, it remains unclear whether these associations can be generalized and applied to fluid-injection- induced seismicity. Analyses presented here using a global dataset of induced seismicity events suggest they can't. Unlike natural earthquakes where tectonic forces generally activate the faults most critically aligned to the far-field in-situ stresses, fluid-injection-induced seismicity is driven mainly by localized pressure perturbations that may activate a fault with a non-critically aligned orientation. These findings are further investigated and supported using 3-D Mohr-circle slip tendency analyses and 3-D numerical models employing a fully-coupled hydro-mechanical bonded-lattice methodology via the commercial hydraulic fracturing numerical simulation program XSite. The combined empirical, analytical and numerical simulation results indicate that under a transform stress regime (SH > SV > Sh), for typical reservoir depths (i.e., 1–6 km), a larger area of the fault affected by the injected fluid pressures is critically stressed compared to a compressional stress regime (SH > Sh > SV), resulting in a larger slip area and an increased likelihood of larger magnitude fluid-injection-induced seismicity events. These findings have important implications for the development of effective hazard mitigation strategies and risk management protocols for fluid-injection-induced seismicity.

The modification of channel system in Tahai lowland irrigation area to improve drainability

The Tahai lowland irrigation area relies on rainwater as a source of irrigation water. The channel system network in Tahai is comb-type with a primary channel connected to the Kahayan River and the end of the primary channel is not connected with other flow sources. The end of the secondary channel is also no longer connected with the collector channel. This condition impacts dissolved solids deposition at the end of the channels. Hydraulic simulations need to be conducted to determine the spread of dissolved solids derived from the fields in the existing water channel system. The existing water channel system could be transformed into a one-way flow system with a right collector channel to expedite water drainage into the Kahayan River. This water channel system plan is also modeled and simulated using HEC-RAS. Hydraulic simulations showed an improvement in channel drainability. At the end of the simulation, the number of dissolved solids in the secondary channel in the one-way flow system was less than that in the existing water channel system.

Water distribution network leak localization with histogram-based gradient boosting

Abstract Accurate and rapid leak localization in water distribution networks is extremely important as it prevents further loss of water and reduces water scarcity. A framework for identifying relevant leak event parameters such as the leak location, leakage area, and start time is presented in this paper. Firstly, the proposed data-driven methodology consists of acquiring pressure data at nodes in the network through hydraulic simulations by randomly changing the leak event initial conditions (leak location, area, and start time). Pressure uncertainties are added to the sensor measurements in order to make the problem more realistic. Secondly, the acquired data are then used to train, test, and validate a machine learning model in order to predict the relevant parameters. The random forest and the histogram-based gradient boosting machine learning algorithms are investigated and compared for the leak detection problem. The proposed approach with the histogram-based gradient boosting algorithm shows high accuracy in predicting the true leak location.

Multi-criteria optimization approach to the design of small dams’ systems along mountainous stream beds

Abstract This paper aims at the optimal design of a system of small solid barrier-type stone dams in a semi-realistic study case, determining the number, location and height of dams and a borrow-pit (BP)'s location for benefit maximization and cost minimization of objectives: (a) maximum flood protection, (b) maximum underlying aquifers' artificial recharge, (c) minimum dams' construction cost and (d) minimum stonework transportation cost. The simplified conceptual model involves no hydraulic simulation; flow characteristics are not considered, while no dam is assumed to affect another dam's benefit/cost values. Hence, all partial benefit/cost values can be separately pre-calculated, for each one of the available dam locations for all available heights and BP locations, deriving from data concerning topography, geology/soil, land uses, construction and transportation costs. Any solution proposing a system of dams of various heights and a BP exhibits a total management value equal to the sum of the respective partial benefit/cost values of each dam. The multi-objective optimization problem is formulated into a single-objective minimization problem; the difference of costs minus benefits is to be minimized. Simple, elitist genetic algorithms (GAs) are used, coupled with sophisticated post-processing of results, able to produce optimized design solutions and strategies.

Recent Advances of Flow Rate Simulation in Gear Pumps

The gear pump is a rotating pump that moves and changes depending on the working volume that is created between the gear and the pump cylinder to transport or pressurize the liquid. It is one of the most widely used hydraulic pumping devices. It has been adopted in road equipment, conveyor systems, and other industrial machineries. Its performance is critical to the engineering equipment. With the development of fluid mechanics, the computational fluid dynamic (CFD) technique is widely used to predict the internal flow filed of gear pumps. CFD can provide researchers more intuitive observation and analysis to help the designers to enhance the effectiveness of gear pump. This paper summarizes the principle of flow simulation methods for gear pump and its applications. The research results and key findings are summarized. Defects of existing research are pointed out and suggestions for future research are provided. To sum up, this paper has a certain reference value for researchers who would like to know the hydraulic simulation process for gear pumps.

Flood inundation mapping of upper Krishna basin using hydrodynamic model

Floodplain management and mapping are new and applied methods in river engineering and for the prediction of flood hazards. Krishna river basin is the second largest river basin in Peninsular India. This basin is one of the flood prone basins in India. The purpose of this study is to focus on the analysis of HEC-RAS to assess and predict the flood depth and spatial extent of flood in the upper Krishna River basin which is drained by Krishna River. To determine extent of inundation, the hydrodynamic model HEC-RAS with ArcGIS was used. For this, discharge data of two months from August and September 2012 has been processed in the study. A methodology was applied to combine hydraulic simulation model, HEC-RAS and GIS analysis for delineation of flood extents and depths for upper Krishna basin in India. Results obtained by using HEC-RAS Model were used by integrating with Arc-GIS to floodplain maps. Through this floodplain maps, the areas that are vulnerable to hazards, have been identified. The results of this research will benefit in future of flood forecasts on a regional scale, also they will be beneficial for water resources management and planning.

A New Porous Nozzle for Aluminum Melts Purification—Preparation and Mathematical–Physical Model

Aluminum and its alloy castings are used more and more widely, and it is particularly important to remove impurities in the alloy. According to the principle of bubble floatation for degassing aluminum melt, a new porous nozzle with controllable pores was developed, and a hydraulic simulation experimental device was studied with the nozzle. The effects of the particle size ratio of the coarse sand to fine sand and volume fraction of fine sand on the porosity of the porous nozzle were studied by orthogonal experiment, and permeability and compressive strength of the porous nozzle were used as test indicators to determine the optimal parameters of preparation for the porous nozzle. The optimal parameters are fine sand of 100 mesh, and fine sand of 50 wt.%, binder of 17.5 wt.%, pore-forming agent of 6 wt.%, and pressure of making sample of 5 MPa. The nozzle with optimal parameters was prepared and tested, and the permeability is 112.2 × 10−12 m2 and the compressive strength is 2.3 MPa. In addition, a physical model of gas transmission in the porous nozzle was proposed. With the increase in the proportion of fine sand, the permeability of the porous nozzle decreases, the compressive strength increases, and the calculated porosity increases. The hydraulic simulation of melt injection was carried out, and the mathematical model for calculating the bubble diameter of bubble floatation was formulated. The model shows that the bubble diameter increases with the increase in gas flow rate. The experiment shows that the prepared porous nozzle has the merits of a simple preparation process and low-cost, which is expected to degas aluminum melts.

NIMPHS: Numerous Instruments to Manipulate and Post-process Hydraulic Simulations

NIMPHS: Numerous Instruments to Manipulate and Post-process Hydraulic Simulations

Linking SVM based habitat model and evolutionary optimisation for managing environmental impacts of hydropower plants

AbstractThe present study proposes a support vector machine (SVM)‐based habitat model linked with evolutionary optimisation to balance the impacts of generating hydropower on the downstream river habitats. This method was applied in the Rajaei reservoir and Tajan River basin in Iran to mitigate the environmental impacts of hydropower plants. SVM model classified the habitat suitability at downstream river in which a sigmoid function considering different slopes was applied. The Nash–Sutcliffe efficiency coefficient as the evaluation index of the habitat model is 0.8, which implies the SVM model is robust to simulate physical habitats. Hydraulic simulation demonstrated that depth and velocity change from zero to 1.79 m and zero to 1.82 m/s, respectively. Most suitable river flow is 7 m3/s downstream of Rajaei reservoir. Five evolutionary algorithms were used to balance environmental impacts with generating hydropower. Finally, a fuzzy technique for order of preference by similarity to ideal solution (FTOPSIS) selected the best optimal solution in the Rajaei reservoir. Based on optimisation results, The simulated annealing (SA) algorithm was the best optimisation method to balance generating hydropower and downstream ecological impacts, in which average habitat suitability is more than 90% of average habitat suitability in the natural flow, while reliability of generating hydropower is 38%. Moreover, SA is able to minimise the average difference between habitat suitability in the optimal release and the natural flow properly. Using the proposed method is recommendable to mitigate the potential impacts of generating hydropower on the downstream river habitats.

Assessment of Object-Level Flood Impact in an Urbanized Area Considering Operation of Hydraulic Structures

Urban flooding has become one of the most common natural hazards threatening people’s lives and assets globally due to climate change and rapid urbanization. Hydraulic structures, e.g., sluicegates and pumping stations, can directly influence flooding processes and should be represented in flood modeling and risk assessment. This study aims to present a robust numerical model by incorporating a hydraulic structure simulation module to accurately predict the highly transient flood hydrodynamics interrupted by the operation of hydraulic structures to support object-level risk assessment. Source-term and flux-term coupling approaches are applied and implemented to represent different types of hydraulic structures in the model. For hydraulic structures such as a sluicegate, the flux-term coupling approach may lead to more accurate results, as indicated by the calculated values of NSE and RMSE for different test cases. The model is further applied to predict different design flood scenarios with rainfall inputs created using Intensity-Duration-Frequency relationships, Chicago Design Storm, and surveyed data. The simulation results are combined with established vehicle instability formulas and depth-damage curves to assess the flood impact on individual objects in an urbanized case study area in Zhejiang Province, China.

Criticality of Isolation Valves in Water Distribution Networks with Hydraulics and Topology

Occasional, random pipe bursts are inevitable in water distribution networks; thus, properly operating isolation valves is critical. During a shutdown, the damaged segment is segregated using the neighbouring valves, causing the smallest isolation possible. This study analyses the importance of isolation valves individually from the perspective of the demand shortfall increment. An in-house, open-source software called STACI performs demand-driven simulations to solve the hydraulic equations with pressure-dependent demand determining the nodal pressures, the volumetric flow rates, and the consumption loss. The system has an additional consumption loss if an isolation valve cannot be closed. The criticality of an isolation valve is the increment in the relative demand shortfall caused by its malfunction. Moreover, centrality indices from complex network theory are applied to estimate the criticality without the need for computationally expensive hydraulic simulations. The distribution of criticality values follows a power-law trend, i.e. some of the isolation valves have significantly higher importance during a shutdown. Moreover, Spearman’s rank correlation coefficients between the centrality and criticality values indicate limited applicability. The criticality analysis can highlight which isolation valves have higher importance during reconstruction planning or maintenance. The Katz and the Degree centrality show a moderate positive correlation to the criticality, i.e., if numerous hydraulic simulations are not feasible, these quantities give an acceptable estimate.

Hydraulic System Design and Simulation of the Lifting Device for the Hanging Barrel Campus Garbage Truck

According to the parameters of the Chengliwei CLW5165ZZZD5 garbage truck, the hydraulic system of the lifting device is designed and simulated. Firstly, the working pressure of the hydraulic system is calculated, and then the type of hydraulic components required is designed and selected; Secondly, the hydraulic system sketch is established through AMESim software and the parameter simulation is carried out; Finally, the variation law of pressure, flow, speed, displacement and other parameters of the hydraulic cylinder is analyzed. The results show that the lifting device can make the Chengliwei self-loading garbage truck work normally, and the design requirements meet the working requirements.

Interactions of Hydraulic Fractures With Grain Boundary Discontinuities in the Near Wellbore Region

AbstractHydraulic fractures often turn or branch, interacting with preexisting discontinuities in the rock mass (e.g., natural fractures or defects). The criteria for fracture penetration or deflection are typically based on the in situ stress, and the angle and strength of discontinuities. However, in hydraulic fracture experiments on carbonate rocks (Naoi et al., 2020, https://doi.org/10.1093/gji/ggaa183), small scale analyses show that the fractures deflected more frequently at discontinuities (grain boundaries) as they propagated farther from the wellbore, a finding not explained by the conventional criteria. Here, we demonstrate that the energy dissipation of a deflecting fracture increases with the distance from the wellbore, such that a propagating hydraulic fracture more easily deflects at a discontinuity from an energetic standpoint. This tendency was confirmed by hydraulic fracture simulations based on a successive energy minimization approach. Our findings, which show that wellbores appreciably affect the behavior of hydraulic fractures, highlight the importance of energetic stability analysis for determining fracture paths.

Evaluation of Casualty Risk Index for Evacuating When Inundation Occurs on Excavation Construction Sites

Recently, inundation accidents occur repeatedly on underground excavation construction sites owing to frequent intensive rainfall events. In the case of the inundation of underground construction sites, injury and drowning accidents may occur on the evacuation route. However, no method or standard for calculating the risk of casualty while evacuating workers has been proposed. In this study, we defined the casualty risk index (CRI) and developed a method for estimating CRI. We adopted the “HV,” which is the product of height (water depth) and velocity (water velocity) recommended by previous researches. The “HV” indicates that humans can walk safely in water flow without stumbling. The proposed method was applied to a hypothetical underground construction site in the city of Yeosoo. ArcGIS Pro was used to model the hypothetical excavation site, and XPSWMM was used to simulate rainfall runoff and two-dimensional hydraulic simulation. While the runoff was flowing into an underground construction site, we simulated the water height and water velocity on the evacuation route to estimate the CRI. The results showed that CRIs from various rainfall scenarios remained in the safe criteria, indicating that workers could safely evacuate from the site in the rainfall scenarios. However, the CRI is influenced by site-based factors, and these factors are discussed.

Interaction of natural and hydraulic fractures: the impact on reservoir pressure buildup and risk of shear fault reactivation in the Upper Devonian Duvernay Formation, Fox Creek, Alberta

The interaction of natural and hydraulic fractures may facilitate lateral fluid propagation in an unconventional reservoir resulting in fast fluid pressure transmission from treatment wells to a fault zone and potential fault shear slip reactivation and associated induced seismicity. Several induced earthquakes (up to 4.1 Mw) occurred since 2013 during hydraulic fracturing of the Upper Devonian Duvernay Formation in the Western Canada Sedimentary Basin. The mechanism of lateral fluid migration in the unconventional reservoir is not well understood. The current study aims to investigate the interaction of natural fractures and hydraulic fractures for the case study in the area south of Fox Creek, where a linear zone of induced earthquakes (up to 3.9 Mw) occurred along a fault in 2015 during hydraulic fracturing of horizontal wells. We analyze the growth of hydraulic fractures in presence of natural fractures, the impact of resulting complex fracture network on fluid transmission and fluid pressure buildup around the treatment wells. Hydraulic fracture modeling (HFM), reservoir simulations and 3D coupled reservoir-geomechanical modeling are applied to match the timing of hydraulic fracture propagation and transmitted fluid pressure increase in the fault zone versus induced earthquake occurrence. HFM results are verified by microseismic clouds distribution. Reservoir simulations are validated by a history matching of fluid injection volume and bottomhole pressure data. Additional HFM simulations are carried out to optimize the pumping schedule in the studied well pad that would help to prevent hydraulic fractures reaching the fault and minimize the risk of induced seismicity.Article highlightsStress anisotropy and simulated natural fractures impact lateral growth of complex hydraulic fractures and reservoir pressure buildup.Predicted fluid pressure transmission to a fault zone results in fault dextral shear slip reactivation matching induced seismicity.Optimized pumping schedule helps to minimize risks of fault reactivation and induced seismicity while preserving overall pad performance.

Hydrological Vulnerability Assessment of Riverine Bridges: The Bajo Grau Bridge Case Study

Analysing the hydrological vulnerability of important structures such as bridges is essential to ensuring people’s safety. This research proposes a methodology to assess the hydrological vulnerability of riverine bridges through a case study of the Bajo Grau Bridge in the city of Arequipa, Peru. Topological and hydrometrical data collection play an important role in the study. A topographic surveying of the bridge and the streambed were carried out, followed by a series of annual maximum flow rates which were compiled, fitted with empirical and theoretical distribution functions, and used in a probability analysis. Based on this process, the flow rates were estimated for six scenarios based on different return periods and critical conditions. Once the hydrological study was completed, the system was modelled using HEC-RAS. The hydraulic simulation, as well as the soil mechanics study, provided the parameters to calculate the scour in the bridge substructure, the potential erosion in the deck, and the possibility of flooding in the superstructure. A hydrological vulnerability assessment matrix with ten criteria subdivided in environmental and physical vulnerabilities was designed and used to determine that the bridge has a high hydrological vulnerability. The proposed methodology can be adapted and transferred to assess other bridges with similar characteristics.

Study on Fuzzy Control of Trawler Winch Based on AMESim

This paper introduces the rapid automatic control module of trawler based on the hydraulic system of ‘Zhejiang fishery scientific research ship No.2’.The hydraulic simulation model of double motor winch system is built in AMESim software, and SIMULINK module in MATLAB software designed closed loop fuzzy PID controller for hydraulic system simulation. through fuzzy PID control technology drives the hydraulic winch to quickly adjust the tension of the traction, maintain the stable balance of the traction force, maintain the optimization of network horizontal expansion, not only improve the fishing efficiency, but also timely and effective protection mesh. the technical achievements formed by the research will enable small and medium-sized trawlers to adjust the tension under various working conditions through the fuzzy PID control system to stabilize the opening shape of the trawl, so as to improve the automation level and fishing efficiency of related trawling equipment, and provide technical support for precision fishing.

An Improved Integrated Numerical Simulation Method to Study Main Controlling Factors of EUR and Optimization of Development Strategy

Gas reservoir numerical simulation is an important method to optimize the development strategy of shale gas reservoirs which has been influenced by the multi-stage fracture. The regular fracture network model was used to build a conventional numerical simulation, in which it was difficult to show the true situation of fracture propagation. However, the physical parameters not only affect the production, but also influence the stimulation effect; moreover, the quality of the fracturing effect also affects the production which causes the input and out parameters to be inaccurate. To solve this problem, the process simulation must be completed from geology to engineering to gas reservoir. The main controlling factors of production are identified with geological and engineering factors such as horizontal stage length, the volume of fracturing fluid, well spacing, production allocation, and proppant mass. Therefore, on the basis of the integrated simulation method of a hydraulic fracturing network simulation and an unstructured grid high-precision numerical simulation, this paper builds an integrated numerical simulation of a shale gas reservoir coupled with geology and engineering to optimize the development strategy with production as the target. Taking four wells of a platform as an example, the EUR (estimated ultimate recovery) has increased by 25% after the optimization of the development strategy.

Design and Simulation of Hydraulic Winch Tension Control for Trawler

The trawler winch is a main winching tool in the fishing operation of trawler. The disturbing influence of various factors such as sea wind and waves, change in the size of the catch and the turning of the fishing vessel during the operation of the trawler will cause unbalanced force on the wire rope of the two winches, which will easily cause the deformation and damage of the fishing net facilities and directly affect the improvement of the fishing yield and increase the harvest. In order to compensate for the change of the tension of the winch tractor during the operation of the trawler, the change of the load tension caused by the wave, or the rotation direction of the fishing vessel, and to ensure the good shape of the net opening, an electro-hydraulic control technology was used to design an automatic trawler tension controller. The tension control method of the trawler is investigated. The tension sensor is used as the input information of the electrical signal of the trawler's left and right trawler, which is measured indirectly and transmitted to the controller for logical operation, and the output torque of the hydraulic motor is changed by controlling the pilot overflow, which drives the trawler winch to adjust the tension of the left and right trawler to achieve the dynamic balance of the control system. In order to solve the problem of the tension of the trawl and the influence of the length change on the trawl, we designed an intelligent control system combining PLC control system and hydraulic system and used AMEsim hydraulic simulation software system to model and simulate it, the results show that without PLC control the torque of hydraulic motor 1 is 2387.7NM, the torque of hydraulic motor 9 is 2148.64NM the difference is 239.06 NM uneven force on both sides of the trailing platform, after adding PLC adjustment torque is obviously controlled torque to maintain about 2300NM, within a certain range to play a reliable adjustment effect.

A convenient and stable graph-based pressure estimation methodology for water distribution networks: Development and field validation

Accurate estimation of unknown nodal pressures (nodal heads) is necessary for efficient operation and management of water distribution networks (WDNs), but existing methods such as hydraulic simulation and data interpolation can hardly reconcile estimation accuracy with model construction and maintenance costs. Recent developments in graph signal processing (GSP) techniques provide us with new tools to utilize information in WDN hydraulics and available measurements. In a pilot study, a graph-based head reconstruction (GHR) method was proposed, which used GSP to reconstruct the spatially slow-varying parts of nodal heads from a limited number of field measurements to approximate original heads. GHR has illustrated the effectiveness and ease of implementation of GSP-based methods. However, due to the ill-conditioning reconstruction process and inherent uncertainties, GHR may show unstable results with large errors if pressure meters are not installed at specific optimized locations, which limits its applicability. To solve this problem and discover a stable and convenient method that can support a wider range of applications, a graph-based head reconstruction method with improved stability (GHR-S) is proposed. GHR-S utilizes a rough estimation of unknown pressures as pseudo measurements, which provide additional constraints and avoid the occurrence of unreasonable results during the reconstruction process. A middle-sized network with synthetic data illustrates the stability, convenience, and accuracy of GHR-S with arbitrary meter locations and uncalibrated model parameters. GHR-S is also applied to a large real-life network with field measurements, and successfully estimates the unknown pressures of 83,000 nodes with only 58 measurements, showing its effectiveness in practical engineering.