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Study on partition of spontaneous combustion danger zone and prediction of self-ignition in coalmine based on numeric simulation 认领 引用 被引量：8
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作者 张辛亥 席光 《Journal of Coal Science & Engineering(China)》 2006年第1期56-59,共4页
By solving steady model of air flow diffusion and chemical reaction in loose coal, distribution of oxygen concentration and flow velocity magnitude were obtained. Compared the simulating results with critic value as w... By solving steady model of air flow diffusion and chemical reaction in loose coal, distribution of oxygen concentration and flow velocity magnitude were obtained. Compared the simulating results with critic value as well as duration of spontaneous combustion from large-scale spontaneous combustion experiment, 'three zones' of spontaneous combustion were partitioned and mining conditions to avoid spontaneous combustion were obtained. The above method was employed to partition 'three zones' in gob of fully mechanized top-coal caving long wall face and got fairly good result. Calculation of the above method is much smaller than simulating the whole process of coal spontaneous combustion, but the prediction precision can satisfy the demand of predicting and extinguishing spontaneous combustion in mining. 展开更多
关键词 coal seam spontaneous combustion prediction numeric simulation flow field
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Aggregate Consumption: An Analysis by Numeric Simulation 认领 引用
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作者 Ricardo Luis Chaves Feij6 《Chinese Business Review》 2017年第8期403-413,共11页
It is estimated that the aggregate consumption behavior of families by computational procedures in an abstract model contemplates the maximization of agent utility in each period （two dates）, the attendance of budge... It is estimated that the aggregate consumption behavior of families by computational procedures in an abstract model contemplates the maximization of agent utility in each period （two dates）, the attendance of budgetary restrictions and the conditions of general equilibrium （without production）. It uses the technique of selection of candidate points in a simulation process with a portfolio of efficient assets and a hypothesis for the process of determining the returns of the securities： A GARCH process. By this technique, it compares the stochastic volatility patterns between the artificial series, obtained in the simulation, and the real series of household aggregate consumption in the US and Brazil. 展开更多
关键词 aggregate consumption numeric simulation general equilibrium stochastic process
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Numeric simulation analysis of load-settlement relation of pile in layer foundation 认领 引用
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作者 王幼青 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2006年第5期576-579,共4页
Considering the level distribution of soil layers, the soils surrounding pile are simulated with level finite layer elements. Supposing that the vertical deformation of the soil elements surrounding pile varies in the... Considering the level distribution of soil layers, the soils surrounding pile are simulated with level finite layer elements. Supposing that the vertical deformation of the soil elements surrounding pile varies in the form of exponent function with radial distance, and considering the nonlinear constitutive relation of stress and strain, the stiffness matrix is established. The mechanics behavior of the pile—soil interface is simulated with a nonlinear interface element. This method can truly express the behavior of the pile-soil system. The load-settlement relation Q-S curves of two big diameter prototype piles on bearing test are analyzed, and satisfying results are obtained. This method is reasonable in theory and feasible in engineering. 展开更多
关键词 layered foundation big diameter pile Q-S curve numeral simulation stiffness matrix
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OptimizationDesign and Numerical Simulation of Variable Tube Diameter Heat Exchanger for Split Air Conditioning Indoor Unit 认领 引用 被引量：1
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作者 Zheming Cheng Xinping Ou Yang +2 位作者 Leren Tao Zihao Wang Ke Sun 《Frontiers in Heat and Mass Transfer》 EI CAS 2026年第1期288-313,共26页
Energy shortage has become one of themost concerning issues in the world today,and improving energy utilization efficiency is a key area of research for experts and scholars worldwide.Small-diameter heat exchangers of... Energy shortage has become one of themost concerning issues in the world today,and improving energy utilization efficiency is a key area of research for experts and scholars worldwide.Small-diameter heat exchangers offer advantages such as reduced material usage,lower refrigerant charge,and compact structure.However,they also face challenges,including increased refrigerant pressure drop and smaller heat transfer area inside the tubes.This paper combines the advantages and disadvantages of both small and large-diameter tubes and proposes a combined-diameter heat exchanger,consisting of large and small diameters,for use in the indoor units of split-type air conditioners.There are relatively few studies in this area.In this paper,A theoretical and numerical computation method is employed to establish a theoretical-numerical calculation model,and its reliability is verified through experiments.Using this model,the optimal combined diameters and flow path design for a combined-diameter heat exchanger using R32 as the working fluid are derived.The results show that the heat transfer performance of all combined diameter configurations improves by 2.79%to 8.26%compared to the baseline design,with the coefficient of performance(COP)increasing from 4.15 to 4.27~4.5.These designs can save copper material,but at the cost of an increase in pressure drop by 66.86%to 131.84%.The scheme IIIH,using R32,is the optimal combined-diameter and flow path configuration that balances both heat transfer performance and economic cost. 展开更多
关键词 Split air condition variable tube diameter enhanced heat transfer numerical simulation structural design optimization
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Numerical and physical simulations of acoustic imaging for adjacent well detection while drilling 认领 引用
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作者 Teng Zhao Gen-Sheng Li +3 位作者 Xiao-Hua Che Wen-Xiao Qiao Jun-Qiang Lu Bai-Yong Men 《Petroleum Science》 SCIE EI CAS CSCD 2026年第3期1197-1219,共23页
With increase in the number of operations involving relief wells,radial wells,U-shaped wells,and other complex well structures,challenges such as collision prevention,obstacle bypassing,and adjacent-well connectivity ... With increase in the number of operations involving relief wells,radial wells,U-shaped wells,and other complex well structures,challenges such as collision prevention,obstacle bypassing,and adjacent-well connectivity achievement during drilling have become inevitable.These challenges necessitate a technology that can accurately detect adjacent wells in real time during drilling operations.As current borehole acoustic reflection imaging technology heavily relies on cable-based logging,it cannot perform real-time detection of adjacent wells during drilling,thereby limiting the drilling efficiency.This study proposes a new adjacent-well-acoustic-detection-while-drilling method that integrates wireline borehole acoustic reflection imaging with drilling technology,along with an adjacent-well imaging method based on compressed sensing(CS).Together,these methods enable high-resolution,real-time detection of the adjacent target wells during drilling,ensuring safe and efficient underground drilling operations.The finite-difference method was used to simulate three-dimensional numerical models under drilling conditions for two scenarios—with and without target wells adjacent to the drilling well.Experimental validation was conducted in a water tank using an adjacent-well-acoustic-detection-while-drilling tool.The simulated target well was imaged using the CS method,and the imaging results were compared with those obtained from numerical and physical simulations,thereby validating the feasibility of the proposed acoustic detection and imaging methods.The results demonstrate that as the radial distance from the target well increases,the PP echo exhibits delayed arrival times and approaches a plane wave while exhibiting amplitude attenuation.Conversely,a linear increase in the target well diameter advances the PP echo arrival time and enhances its amplitude proportionally.When the target and drilling wells are approximately parallel with a small intersection angle,PP echoes yield better detection results than SS echoes;when the wells are coplanar with a large intersection angle,SS echoes provide better detection results.The receiver element aligned with the target well's azimuth detects all echo modes with the earliest arrival times and highest amplitudes.The adjacent-well imaging method based on CS offers very high spatial resolution,with target wells appearing as local amplitude maxima.This feature enables the precise determination of their azimuth and inclination relative to the drilling wells.The findings offer a solid physical and methodological foundation for real-time detection of adjacent wells during drilling operations and demonstrate enormous theoretical and engineering application potential. 展开更多
关键词 Adjacent well detection Acoustic logging while drilling Compressed sensing Numerical simulation Physical simulation
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Numerical simulation of wind sand flow fields and deposition-erosion characteristics in the bridge-road transition section under different wind angles 认领 引用
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作者 ZHANG Xingxin ZHANG Kai +2 位作者 LIU Benli ZHAO Yanhua WANG Zhenghui 《Journal of Mountain Science》 SCIE CSCD 2026年第5期2427-2439,共13页
Railways in desert suffer from windblown sand hazards,in which the problems at bridge-road transitions are usually more serious.However,the evolution of wind-sand flow fields and the associated deposition-erosion patt... Railways in desert suffer from windblown sand hazards,in which the problems at bridge-road transitions are usually more serious.However,the evolution of wind-sand flow fields and the associated deposition-erosion patterns around bridge-road transitions under different wind directions remain limited.In this study,numerical simulations are employed to study the influence of wind angle on the flow field structure,wind profiles,horizontal wind speed distribution,and sand deposition-erosion behavior around the bridge-road transition.The results indicate that as the wind angle increases,the leeward vortex recirculation zone expands,the peak of the vertical wind speed profile increases,and the horizontal wind speed decreases.With respect to deposition-erosion patterns,the sand deposition length on the windward sides of both the bridge pier and the bridge-road transition decreases with increasing wind angle.In contrast,the deposition length on the leeward side increases.Specifically,when the wind angle increases from 60°to 90°,the windward deposition length at the bridge-road transition decreases from 1.99H to 1.49H(H,the clear height of bridge),while the leeward deposition expands from 0.70H to 13.28H.In addition,the bridge-road transition section serves as a channel for sand transport,promoting the migration of sand toward the subgrade.A smaller wind angle enhances the lateral guidance effect on the wind-sand flow,resulting in a greater sand deposition length on the leeward side of the subgrade.Therefore,the prevention and control of sand hazards in the bridge-road transition section should not be neglected.It is necessary to regularly remove accumulated sand to prevent its spread from the transition section to the subgrade,which could threaten traffic safety. 展开更多
关键词 Wind angles Bridge-road transition sections Wind sand flow field Deposition-erosion characteristics Numerical simulation
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Numerical calculation method of virtual nodes in complex structural composites: mechanical properties characterization and numerical simulation of combined Wbraid/Al/Epoxy functional structural materials 认领 引用
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作者 Zhenhui He Enling Tang +3 位作者 Zhe Zhai Wenjin Yao Ruizhi Wang Yafei Han 《Defence Technology（防务技术）》 SCIE EI CAS CSCD 2026年第3期149-165,共17页
Existing numerical methods for complex composites, such as multiscale simulation and neural network algorithms, face significant limitations. Multiscale techniques are often prohibitively expensive for large models, w... Existing numerical methods for complex composites, such as multiscale simulation and neural network algorithms, face significant limitations. Multiscale techniques are often prohibitively expensive for large models, while neural networks struggle to represent underlying microscopic material properties. To overcome these challenges, a meso-micro scale numerical method using a virtual node approach is developed in this study. A Wbraid/Al/Epoxy functional structural material is fabricated, and a representative periodic unit cell is identified based on its architecture. The complex structure is then discretized into nodes, and mechanical interactions are governed by pre-defined computation rules. This virtual node method is systematically compared against both multiscale simulation and a neural network algorithm, with validation provided through mechanical experiments. The results demonstrate that the nodal operation strategy significantly reduces computational resource requirements. By quantifying microscopic bonding with coefficients, explicit interface treatment is avoided, granting the method strong adaptability to lattice materials. The method can simulate extremely complex structures using parameters from simple tests and is suited for large systems. Compared to three-point bending experiments, errors for multiscale, virtual node, and neural network methods were 12.4%, 6.9%, and 34.5%, respectively. Under dynamic compression, the errors were 2.7%, 9.3%, and 15.43%. The virtual node method demonstrated superior accuracy under static conditions, enabling efficient prediction and auxiliary development of complex structural materials. 展开更多
关键词 Functional composites Complex structure Meso-micro scale Virtual node calculation method Numerical simulation
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Numerical simulations of geological CO2 storage in a gas reservoir of the B depression,Pearl River Mouth Basin 认领 引用
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作者 Chen Wang Shaocheng Luo +3 位作者 Yu Mou Jianhui Zeng Yawen Ren Chengfei Guo 《Energy Geoscience》 EI CAS CSCD 2026年第1期103-115,共13页
Geological CO2 storage is a promising strategy for reducing greenhouse gas emissions and has become a growing focus of research and deployment.This paper presents numerical simulations of CO2 injection and stora... Geological CO2 storage is a promising strategy for reducing greenhouse gas emissions and has become a growing focus of research and deployment.This paper presents numerical simulations of CO2 injection and storage in a depleted gas reservoir within the B Depression and evaluates associated CO2 trapping mechanisms.In the base case,a constant injection rate of 3500 m3/d over fifteen years resulted in a cumulative injection of 19.2×106 m3.The CO2 plume expanded radially during injection and subsequently migrated up-dip under buoyancy forces.The final stored mass of CO2 in the reservoir was 10.6 million tonnes(Mt),representing less than 10% of its theoretical capacity.The plume was projected to reach the entrapment crest and the top of the reservoir within a century,indicating secure long-term containment.Structural,stratigraphic,and residual trapping dominate in Reservoir A(approximately 90%).Anticlinal closures with thick overlying mudstones in the Zhujiang Formation provide effective seals,further enhancing storage security.Reservoir properties and heterogeneity play a crucial role in controlling CO2 storage.However,reservoir heterogeneity exerts only a limited influence when intrinsic properties are favorable.Overall,the study and implementation of CO2 capture,utilization,and storage(CCUS)in China's offshore basins show promising prospects. 展开更多
关键词 Geological CO2storage CO2plume Gas reservoir Numerical simulation China offshore
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Numerical simulation study on intermittent swimming characteristics of octopus based on the eight-arm undulation mechanism 认领 引用
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作者 Wenhua Chu Liuyang Pan +3 位作者 Yaze Song Jifeng Yan Qiaoli Zhou Zijing Zhao 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2026年第3期471-488,共18页
The swimming mechanism of octopuses has been a hot topic in the field of biology in recent years.Existing research primarily focuses on the influence of morphological parameters on octopus swimming ability;the impact ... The swimming mechanism of octopuses has been a hot topic in the field of biology in recent years.Existing research primarily focuses on the influence of morphological parameters on octopus swimming ability;the impact of kinematic parameters remains relatively unexplored.This study focuses on the swimming posture and movement characteristics of octopuses,formulating a synchronized flexible undulation equation for their eight arms.Based on this,computational fluid dynamics combined with dynamic mesh technology is employed to numerically simulate their propulsion mechanism and swimming characteristics.Furthermore,by varying the hover coast time ratio and duty cycle,the influence of different kinematic parameters on propulsion efficiency is explored(close phase after hover coast time ratio is defined as DSC;open phase after hover coast time ratio is defined as DSO,and the duty cycle is defined as DC).The results indicate that the periodic opening and closing motion of the octopus leads to the alternating generation and dissipation of reverse vortices in the wake field,with the jet effect between them being the primary source of propulsion.When DSC=0.30,the forward speed of the octopus after 1 s is only 6%lower than that without hover coast behavior.When DSO=0.30,the peak thrust coefficient of the octopus reaches 0.82,which is 15%higher than that without hover coast behavior,indicating the highest burst acceleration.On the other hand,when DC=0.67,under asymmetric periodic swimming with fast-closing-slow-opening,the average thrust coefficient reaches 0.26,an increase of 23.8%compared to uniform opening-closing periodic swimming,while the average lateral force coefficient decreases by 66.7%.In this scenario,the octopus can achieve better forward propulsion and maintain stable movement.The findings of this study provide valuable insights for research on the intermittent swimming behavior of octopuses and underwater vehicles. 展开更多
关键词 Octopus Swimming characteristics Eight-arm undulation motion Numerical simulation
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Numerical Simulation of the Welding Deformation of Marine Thin Plates Based on a Temperature Gradient-thermal Strain Method 认领 引用
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作者 Lin Wang Yugang Miao +3 位作者 Zhenjian Zhuo Chunxiang Lin Benshun Zhang Duanfeng Han 《哈尔滨工程大学学报（英文版）》 CSCD 2026年第1期122-135,共14页
Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The t... Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The traditional thermal elastic-plastic finite element method(TEP-FEM)can accurately predict welding deformation.However,its efficiency is low because of the complex nonlinear transient computation,making it difficult to meet the needs of rapid engineering evaluation.To address this challenge,this study proposes an efficient prediction method for welding deformation in marine thin plate butt welds.This method is based on the coupled temperature gradient-thermal strain method(TG-TSM)that integrates inherent strain theory with a shell element finite element model.The proposed method first extracts the distribution pattern and characteristic value of welding-induced inherent strain through TEP-FEM analysis.This strain is then converted into the equivalent thermal load applied to the shell element model for rapid computation.The proposed method-particularly,the gradual temperature gradient-thermal strain method(GTG-TSM)-achieved improved computational efficiency and consistent precision.Furthermore,the proposed method required much less computation time than the traditional TEP-FEM.Thus,this study lays the foundation for future prediction of welding deformation in more complex marine thin plates. 展开更多
关键词 Marine thin plate Welding deformation Numerical simulation Temperature gradient-thermal strain method Shell element
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Direct numerical simulations of high-pressure impinging-jet atomization:Interfacial evolutions and spray characteristics 认领 引用
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作者 Bo WANG Erjun WU +4 位作者 Anlong YANG Feng ZHANG Baoe YANG Qingquan LIU Xiaodong CHEN 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2026年第3期158-174,共17页
This study presents a numerical investigation of impinging-jet atomization across various Weber numbers(We) under high backpressure conditions.Using the volume-of-fluid method,adaptive mesh refinement,and the iso Adve... This study presents a numerical investigation of impinging-jet atomization across various Weber numbers(We) under high backpressure conditions.Using the volume-of-fluid method,adaptive mesh refinement,and the iso Advector interface reconstruction technique,atomization characteristics are simulated and analyzed for different values of We.The results indicate that the geometry induces turbulent jets,which drive turbulent atomization through the shear interactions at the gas–liquid interface.The key observed phenomena include the interaction of impact waves with liquid sheet perforation and the breakup of web of ligaments,both of which are prominent under high backpressure conditions.A novel method,based on the threshold velocity of spray droplet groups,is employed to quantitatively measure the spreading angle,showing that the angle increases with We in both front and side views.Additionally,the Sauter mean diameter of droplets follows power-law scaling with exponents of-1/3 in the upstream region and-1/2 in the downstream region,while the droplet size distribution conforms to a log-normal profile.This research provides valuable insights into interface evolution and droplet characteristics during impingingjet atomization under high backpressure,offering essential guidance for optimizing industrial atomization processes. 展开更多
关键词 Direct numerical simulations High-pressure Impinging-jet atomization Interfacial evolutions Spray characteristics
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3D finite-difference numerical simulation of the gravitational field using a preconditioned GMRES iterative solver 认领 引用
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作者 TONG Xiao-zhong XIE Wei +3 位作者 MA Hui-ying WEN Xin-yue ZHU Wen-di ZHANG Chen 《Journal of Central South University》 SCIE EI CAS CSCD 2026年第2期847-860,共14页
With the evolution of geophysical surveys from traditional two-dimensional(2 D)to three-dimensional(3 D)models,the resulting large data volumes pose significant challenges to inversion,particularly when resolving larg... With the evolution of geophysical surveys from traditional two-dimensional(2 D)to three-dimensional(3 D)models,the resulting large data volumes pose significant challenges to inversion,particularly when resolving large-scale 3 D structures.A direct solver for solving an ill-conditioned linear system resulting from the finite-difference approximation of a boundary value problem requires more memory and time than iterative solvers.To overcome this limitation,an efficient iterative solver for 3 D finite-difference approach is introduced to calculate the 3 D gravitational potential and the associated gravitational field.Firstly,the boundary value problem associated with 3 D gravitational potential is discretized using central finite-difference technique based on right rectangular prismatic grids.The resulting large unsymmetric sparse systems are then solved using the generalized minimal residual algorithm(GMRES)iterative solver in combination with incomplete LU factorization.Secondly,to obtain high-accuracy partial derivatives of gravitational potential,a high-degree Lagrange interpolation scheme is employed.Finally,three density models are applied to test the accuracy,reliability,and flexibility of our 3 D finite-difference algorithm.All computational results demonstrate that our method provides an accurate approximation of the gravitational field and is applicable to 3 D forward modeling. 展开更多
关键词 3 D gravitational potential boundary value problem numerical simulation finite-difference algorithm GMRES iterative solver
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Coupled water-vapor-heat-salt transport mechanisms in sulfate saline soils under the pot cover effect:numerical simulation and experimental validation 认领 引用
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作者 ZHANG Ruiling CHOU Yaling +2 位作者 ZHANG Mingli ZHOU Fengxi LIU Hongbo 《Journal of Mountain Science》 SCIE CSCD 2026年第7期3477-3504,共28页
The pot cover effect can induce various forms of distress in cover layer engineering,such as salt heave,cracking,and differential settlement,with water vapor migration being the primary cause.However,current research ... The pot cover effect can induce various forms of distress in cover layer engineering,such as salt heave,cracking,and differential settlement,with water vapor migration being the primary cause.However,current research on the pot cover effect in saline soils rarely takes into account the water vapor transport process.Therefore,elucidating the coupled transport mechanisms of water,vapor,heat,and salt in saline soils under this effect is crucial for the prevention and control of related engineering hazards.This study developed a numerical model describing the coupled water-vapor-heat-salt transport in unsaturated saline sulfate soil and validated its reliability through laboratory unidirectional freezing column tests.Based on this model,a numerical analysis was conducted to investigate the formation mechanism of the pot cover effect during the unidirectional freezing of the saline soil.The results indicate that the moisture and salt fields exhibit a typical bimodal distribution pattern,with peaks located at the soil surface and the freezing front,respectively.Compared with the initial water content of 19% and initial salt content of 1%,the total water content at the surface and freezing front increased by 21% and 13%,respectively,while the total salt content rose by 1.25% and 0.5%,respectively.Liquid water flux upward in the unfrozen zone,while it approaches zero within the frozen zone.In contrast,both vapor flux and solute flux migrate upward throughout the entire soil column,reaching their maximum values at the freezing front.Compared to models that neglect vapor transport,the simulated total moisture content at the surface was 12% higher in the model accounting for vapor movement,indicating that water vapor migration is a key factor contributing to moisture accumulation at the surface.The findings of this study can provide a theoretical basis for preventing engineering hazards associated with the pot cover effect in saline soils. 展开更多
关键词 Seasonally frozen soil Pot cover effect Sulfate saline soil Water-vapor-heat-salt coupling Numerical simulation Moisture and salt transport
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Numerical simulation of multi-gasbag propulsion system and attitude control of release unit based on two-phase flow method 认领 引用
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作者 Xinggan Lu Shenshen Cheng +2 位作者 Xiaoting Cui Kun Jiang Hao Wang 《Theoretical & Applied Mechanics Letters》 EI CAS CSCD 2026年第2期65-79,共15页
Collaborative technology for the remote,large-scale deployment of drones using dispersal systems holds significant potential in applications such as post-disaster rescue,which must balance low overload with high thrus... Collaborative technology for the remote,large-scale deployment of drones using dispersal systems holds significant potential in applications such as post-disaster rescue,which must balance low overload with high thrust,in addition to precisely controlling the separation attitude.To address these issues,this paper introduces a multi-gasbag propulsion system with a high aspect ratio that coordinates multiple gasbags to generate sufficient thrust.By adjusting the inlet size of the gasbag,the separation behavior of the release unit can be accurately controlled.A multidimensional two-phase flow model is established,accompanied by both combustion and flow experiments and a double-gasbag propulsion experiment.The results demonstrate that the proposed mathematical model is accurate,effectively captures the pressure fluctuations and spatiotemporal distribution of flow field parameters,and determines the separation attitude of the release unit.For the cases studied in this paper,the pressure at the gasbag inlet(z=650 mm)is the dominant factor during the gasbag propulsion response,causing the release unit to rotate counterclockwise when the gasbag inlet sizes are identical.Increasing the inlet size at z=50 mm compensates for the adverse effects of uneven axial pressure distribution,thereby achieving a neutral separation for the release unit.When the radii r1 and r2 vary between 2 and 12 mm,the angular velocity and attitude angle of the release unit are found to range from-15.50 to 15.20 rad/s and from-0.109 to 0.106 rad,respectively. 展开更多
关键词 Two-phase flow Dispersal technology Parameter distribution Attitude control Numerical simulation
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Numerical Simulation of Cross-Layer Propagation Mechanisms for Hydraulic Fractures in Deep Coal-Rock Formations 认领 引用
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作者 Zhirong Jin Xiaorui Hou +4 位作者 Yanrong Ge Tiankui Guo Ming Chen Shuyi Li Tianyu Niu 《Energy Engineering》 EI 2026年第2期369-391,共23页
Hydraulic fracturing serves as a critical technology for reservoir stimulation in deep coalbed methane(CBM)development,where the mechanical properties of gangue layers exert a significant control on fracture propagati... Hydraulic fracturing serves as a critical technology for reservoir stimulation in deep coalbed methane(CBM)development,where the mechanical properties of gangue layers exert a significant control on fracture propagation behavior.To address the unclear mechanisms governing fracture penetration across coal-gangue interfaces,this study employs the Continuum-Discontinuum Element Method(CDEM)to simulate and analyze the vertical propagation of hydraulic fractures initiating within coal seams,based on geomechanical parameters derived from the deep Benxi Formation coal seams in the southeastern Ordos Basin.The investigation systematically examines the influence of geological and operational parameters on cross-interfacial fracture growth.Results demonstrate that vertical stress difference,elastic modulus contrast between coal and gangue layers,interfacial stress differential,and interfacial cohesion at coal-gangue interfaces are critical factors governing hydraulic fracture penetration through these interfaces.High vertical stress differences(>3 MPa)inhibit interfacial dilation,promoting predominant crosslayer fracture propagation.Reduced interfacial stress contrasts and enhanced interfacial cohesion facilitate fracture penetration across interfaces.Furthermore,smaller elastic modulus contrasts between coal and gangue correlate with increased interfacial aperture.Finally,lower injection rates effectively suppress vertical fracture propagation in deep coal reservoirs.This study elucidates the characteristics and mechanisms governing cross-layer fracture propagation in coal–rock composites with interbedded partings,and delineates the dynamic evolution laws and dominant controlling factors involved.Thefindings provide critical theoretical insights for the optimization of fracture design and the efficient development of deep coalbed methane reservoirs. 展开更多
关键词 Deep coal-rock formations cross-layer fracturing fluid-solid coupling fracture propagation behavior numerical simulation
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Direct numerical simulation of the effect of wall-generated positive/negative Reynolds shear stress on wall friction resistance in turbulent boundary layers 认领 引用
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作者 Qian-Jin Xia Hongsheng Zhang +1 位作者 Long Lian Yuan Xue 《Theoretical & Applied Mechanics Letters》 EI CAS CSCD 2026年第2期57-64,共8页
Direct numerical simulation of spatially developing turbulent boundary layers with periodic blowing or suction through a series of inclined slots in a control region was conducted.The wall-generated Reynolds shear str... Direct numerical simulation of spatially developing turbulent boundary layers with periodic blowing or suction through a series of inclined slots in a control region was conducted.The wall-generated Reynolds shear stress(RSS),i.e.,the RSS on the wall in the control region,is generated through the control scheme.The effect of the wall-generated RSS on friction drag was examined via a series of simulations.The Reynolds numbers of the turbulent boundary layers investigated vary from 300-860 on the basis of the external flow velocity and the momentum thickness.The proposed control scheme was used to verify the relationship between the wall-generated RSS and skin friction drag,and it was found that a wall-generated negative RSS(net positive)increases the skin friction drag,whereas a wall-generated positive RSS(net negative)reduces it.The proposed control method can provide a high drag reduction rate,and even negative resistance and backflow can be observed. 展开更多
关键词 Turbulent boundary layer Turbulence control Drag reduction Wall-generated Reynolds shear stress Direct numerical simulation
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Experimental and numerical simulation of gas injection for enhanced oil recovery in naturally fractured condensate gas reservoirs 认领 引用
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作者 Bin Ju Ping Guo +3 位作者 Yizhong Zhang Long Yang Zhouhua Wang Maolin Zhang 《Natural Gas Industry B》 2026年第2期164-191,共28页
Gas condensate reservoirs constitute important natural gas resources;however,their development is frequently hindered by condensate banking and complex multiphase flow behavior.Naturally fractured gas condensate reser... Gas condensate reservoirs constitute important natural gas resources;however,their development is frequently hindered by condensate banking and complex multiphase flow behavior.Naturally fractured gas condensate reservoirs present additional challenges because their dualporosity and dual-permeability structure induces strong phase redistribution and nonuniform flow between matrix and fracture systems,thereby complicating reservoir characterization and compositional simulation.In this study,integrated laboratory experiments and numerical simulations were performed for a deep,rich,naturally fractured gas condensate reservoir.Depletion,diffusion,and core flooding experiments involving CO2,N2,and dry gas injection were conducted using fractured core samples.A dual-porosity and dual-permeability compositional model incorporating a five-spot well pattern was established to evaluate condensate liquid recovery and to quantify mass transfer between matrix and fracture networks.The effect of matrix-fracture permeability contrast on production performance was systematically analyzed.The results indicate that matrix permeability is a primary parameter controlling recovery in gas condensate reservoirs.The ratio of matrix-fracture permeability contrasts exerts a stronger influence on condensate liquid recovery than on natural gas recovery.Pressure maintenance through gas injection is critical for improving recovery performance.When reservoir pressure declines below the dew-point pressure,early gas injection is recommended to mitigate condensate accumulation in the near-well region.Among the injected gases evaluated,CO2 demonstrated superior pressure maintenance performance compared with N2 and dry gas. 展开更多
关键词 Gas condensate reservoir Dual porosity and dual permeability Enhanced oil recovery Carbon capture Utilization and storage(CCUS) Numerical simulation
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Mutual influence mechanism between soft soil interlayers and shield tunnels under seismic action:Laboratory tests and numerical simulations 认领 引用
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作者 Xinwei Tang Gaozhi Xin Danqing Song 《Earthquake Research Advances》 CAS CSCD 2026年第1期64-74,共11页
Soft soil is widely distributed and has complex origins.Shield tunnels are inevitably constructed within soft soil interlayers,and under seismic action,tunnels may be subject to severe damages.On the basis of actual e... Soft soil is widely distributed and has complex origins.Shield tunnels are inevitably constructed within soft soil interlayers,and under seismic action,tunnels may be subject to severe damages.On the basis of actual engineering,this study utilized dynamic triaxial testing to investigate the dynamic properties of soft soil.Using the PIMY constitutive model,the seismic subsidence characteristics of the soft soil were characterized,and a refined finite element model was established to study the mutual influence mechanism between the soft soil layer and shield tunnels via the open-source software framework OpenSees.The results demonstrate that soil exhibits a softening effect under dynamic loading;soft soil with better structural integrity is less prone to seismic subsidence;and the greater the inertial force acting on the soft soil,the greater the likelihood of settlement.Under seismic action,the presence of the shield tunnel exacerbates the settlement of the soft soil,as the surrounding soil experiences significant inertial forces from the tunnel structure,hindering drainage and accelerating the accumulation of pore water pressure;The soft soil itself has large deformation and displacement under the action of earthquake,which leads to the great stress,deformation,and displacement of the structure.The arch foot position of the tunnel is identified as the most vulnerable to damage. 展开更多
关键词 Soft soil interlayers Shield tunnels Seismic response Numerical simulation Influence mechanism
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Theoretical model and numerical simulation research on minimum overburden thickness of TBM excavation based on surrounding rock arching theory 认领 引用
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作者 ZHOU Zhong SUI Yuchao YAN Haitao 《Journal of Southeast University(English Edition)》 EI CAS 2026年第1期12-25,共14页
Based on the surrounding rock arching and hingeless arch structure theories,a theoretical formula for the minimum overburden thickness was derived.By substituting different mechanical parameters of multiple tunnels at... Based on the surrounding rock arching and hingeless arch structure theories,a theoretical formula for the minimum overburden thickness was derived.By substituting different mechanical parameters of multiple tunnels at home and abroad into this formula,minimum self-supporting arch formulas under different surrounding rock classes were obtained.Based on the actual engineering case of a dual-mode shield tunnel,a numerical model for the tunnel boring machine excavation mode was established to verify the theoretical formulas.Next,three surrounding rock classes,four soil layer thickness gradients,and twelve overburden thickness gradients were designed,resulting in 144 models formed by the combination of the three factors.Uniform tests were conducted,and the pressure arch heights under different surrounding rock classes were obtained.The results show that in the theoretical formulas,the tunnel radius has a linear positive correlation with the pressure arch height,while the tunnel depth has a linear positive correlation with the square of the pressure arch height.According to numerical simulation results,the pressure arch height increases with the increase of the overburden thickness and then tends toward a critical value of twice the tunnel diameter.Finally,the results of the numerical model are in good agreement with those calculated using the theoretical formulas,verifying the rationality of the established theoretical formulas. 展开更多
关键词 minimum overburden thickness tunnel boring machine(TBM) pressure arch numerical simulation self-supporting arch
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Qualitative Analysis and Numerical Simulation of a Predator-Prey Model for Invertebrate Predators in Aquatic Population Ecosystem 认领 引用
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作者 WANG Lijuan JIANG Hongling +3 位作者 HE Jinchan ZHAO Qi JING Miaomiao ZHAO Jihong 《Wuhan University Journal of Natural Sciences》 CAS CSCD 2026年第2期101-111,共11页
The predation mechanism of invertebrates(e.g.,Tortanus dextrilobatus)on plankton in aquatic population ecosystem is a significant research topic.In this paper,the interaction between invertebrates and plankton is simu... The predation mechanism of invertebrates(e.g.,Tortanus dextrilobatus)on plankton in aquatic population ecosystem is a significant research topic.In this paper,the interaction between invertebrates and plankton is simulated by a modified Leslie-Gower predator-prey model.Using the theory of reaction-diffusion equations,a priori estimate,existence,uniqueness and stability conditions of the positive steady state solution are established.Furthermore,numerical simulations are conducted to quantitatively analyze the dynamical behavior.The research shows that as long as the Allee effect constant satisfies the appropriate relationship and the growth rates of predator and prey are appropriately large,the predator and prey can not only coexist,but also the coexistence mode is unique and stable under low predation-rate.In addition,the numerical simulations show that the coexistence may be stable under high predation-rate.Meanwhile,with the increase of predation rate,the population density of predators will decrease. 展开更多
关键词 predator-prey model aquatic population ecosystem Allee effect Ivlev functional response positive steady-state solutions numerical simulation
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