Hydrodynamic cavitation,as an efficient technique applied in many physical and chemical treatment methods,has been widely used by various industries and in several technological fields.Relevant generators,designed wit...Hydrodynamic cavitation,as an efficient technique applied in many physical and chemical treatment methods,has been widely used by various industries and in several technological fields.Relevant generators,designed with specific structures and parameters,can produce cavitation effects,thereby enabling effective treatment and reasonable transformation of substances.This paper reviews the design principles,performance,and practical applications associated with different types of cavitation generators,aiming to provide theoretical support for the optimization of these systems.It systematically analyzes the underpinning mechanisms and the various factors influencing the cavitation phenomena,also conducting a comparative analysis of the performance of different types of generators.Specific applications dealing with wastewater treatment,chemical reaction acceleration,and other fields are discussed together with the advantages,disadvantages,and applicability of each type of cavitation generator.We also explore research progress in areas such as cavitation stability,energy efficiency,and equipment design upgrades.The study concludes by forecasting the application prospects of intelligent design and computational fluid dynamics(CFD)in optimizing and advancing cavitation generators.It proposes new ideas for the further development of cavitation technology and highlights directions for its widespread future application.展开更多
The objective of this study is to propose an optimal plant design for blue hydrogen production aboard a liquefiednatural gas(LNG)carrier.This investigation focuses on integrating two distinct processes—steam methaner...The objective of this study is to propose an optimal plant design for blue hydrogen production aboard a liquefiednatural gas(LNG)carrier.This investigation focuses on integrating two distinct processes—steam methanereforming(SMR)and ship-based carbon capture(SBCC).The first refers to the common practice used to obtainhydrogen from methane(often derived from natural gas),where steam reacts with methane to produce hydrogenand carbon dioxide(CO_(2)).The second refers to capturing the CO_(2) generated during the SMR process on boardships.By capturing and storing the carbon emissions,the process significantly reduces its environmental impact,making the hydrogen production“blue,”as opposed to“grey”(which involves CO_(2) emissions without capture).For the SMR process,the analysis reveals that increasing the reformer temperature enhances both the processperformance and CO_(2) emissions.Conversely,a higher steam-to-carbon(s/c)ratio reduces hydrogen yield,therebydecreasing thermal efficiency.The study also shows that preheating the air and boil-off gas(BOG)before theyenter the combustion chamber boosts overall efficiency and curtails CO_(2) emissions.In the SBCC process,puremonoethanolamine(MEA)is employed to capture the CO_(2) generated by the exhaust gases from the SMR process.The results indicate that with a 90%CO_(2) capture rate,the associated heat consumption amounts to 4.6 MJ perkilogram of CO_(2) captured.This combined approach offers a viable pathway to produce blue hydrogen on LNGcarriers while significantly reducing the carbon footprint.展开更多
This paper aims to numerically explore the characteristics of unsteady cavitating flow around a NACA0015 hydrofoil,with a focus on vorticity attributes.The simulation utilizes a homogeneous mixture model coupled with ...This paper aims to numerically explore the characteristics of unsteady cavitating flow around a NACA0015 hydrofoil,with a focus on vorticity attributes.The simulation utilizes a homogeneous mixture model coupled with a filter-based density correction turbulence model and a modified Zwart cavitation model.The study investigates the dynamic cavitation features of the thermal fluid around the hydrofoil at various incoming flow velocities.It systematically elucidates the evolution of cavitation and vortex dynamics corresponding to each velocity condition.The results indicate that with increasing incoming flow velocity,distinct cavitation processes take place in the flow field.展开更多
Ultra-precision components have been widely used to produce advanced optoelectronic equipment.The so-called Electric field enhanced UltraViolet-Induced Jet Machining(EUV-INCJM)is an ultra-precision method that can ach...Ultra-precision components have been widely used to produce advanced optoelectronic equipment.The so-called Electric field enhanced UltraViolet-Induced Jet Machining(EUV-INCJM)is an ultra-precision method that can achieve sub-nanometer level surface quality polishing.This study focuses on the application of the EUV-INCJM with different nozzle structures to a single-crystal of silicon.Two kinds of electro-optic-liquid coupling nozzles with single-jet and multi-jet focusing structures are proposed accordingly.Simulations and experiments have been conducted to verify the material removal performance of these nozzles.The simulation results show that,under the same condition,the flow velocity of the single-jet nozzle is 1.05 times higher than that achieved with the multi-jet configuration,while the current density of the latter is 1.63 times higher than that of the single-jet nozzle.For the single-crystal silicon,the material removal efficiency of the multi-jet focusing nozzle exceeds by about 1.4 times that of the single-jet.These results confirm that the material removal ability of the multi-jet configuration is more suitable for ultra-smooth surface polishing.The surface roughness of Si workpiece was reduced from Rq 1.55 to Rq 0.816 nm with valleys and peaks on its surface being almost completely removed.展开更多
Understanding the complex interaction between heat and mass transfer in non-Newtonian microflows is essential for the development and optimization of efficient microfluidic and thermal management systems.This study in...Understanding the complex interaction between heat and mass transfer in non-Newtonian microflows is essential for the development and optimization of efficient microfluidic and thermal management systems.This study investigates the magnetohydrodynamic(MHD)thermosolutal convection of a Casson fluid within an inclined,porous microchannel subjected to convective boundary conditions.The nonlinear,coupled equations governing momentum,energy,and species transport are solved numerically using the MATLAB bvp4c solver,ensuring high numerical accuracy and stability.To identify the dominant parameters influencing flow behavior and to optimize transport performance,a comprehensive hybrid optimization framework—combining a modified Taguchi design,Grey Relational Analysis(GRA),and Principal Component Analysis(PCA)—is proposed.This integrated strategy enables the simultaneous assessment of skin friction,Nusselt number,and Sherwood number,providing a rigorous multi-objective evaluation of system performance.Comparative validation with benchmark results from the literature confirms the accuracy and reliability of the present formulation and its numerical implementation.The results highlight the intricate coupling among flow slip,buoyancy effects,and convective transport mechanisms.Increased slip flow enhances axial velocity,while a higher solutal Biot number intensifies concentration gradients near the channel walls.Conversely,a lower thermal Biot number diminishes the temperature field,indicating weaker heat transfer across the boundaries.PCA results reveal that the first principal component(PC1)accounts for most of the system variance,demonstrating the dominant influence of coupled flow and transport parameters on overall system performance.展开更多
In the early stages of oil exploration,oil is produced through processes such as well drilling.Later,hot water may be injected into the well to improve production.A key challenge is understanding how the temperature a...In the early stages of oil exploration,oil is produced through processes such as well drilling.Later,hot water may be injected into the well to improve production.A key challenge is understanding how the temperature and velocity of the injected hot water affect the production rate.This is the focus of the current study.It proposes variableviscosity mathematical models for heat and water saturation in a reservoir containing Bonny-light crude oil,with the aim of investigating the effects of water temperature and velocity on the recovery rate.First,two sets of experimental data are used to construct explicit temperature-dependent viscosity models for Bonny-light crude oil and water.These viscosity models are incorporated into the Buckley-Leverette equation for the dynamics of water saturation.A convex combination of the thermal conductivities of oil and water is used to formulate a heat propagation model.A finite volume scheme with temperature-dependent HLL numerical flux is proposed for saturation,while a finite difference approximation is derived for the heat model,both on a staggered grid.The convergence of the method is verified numerically.Simulations are conducted with different parameter values.The results show that at a wall temperature of 10℃,an increase in the injection velocity from 0.1 to 0.25 increases the production rate from 8.33%to 20.8%.Meanwhile,with an injection velocity of v=1,an increase in the temperature of the injected water from 25℃ to 55℃ increases production rate from 59.48%to 61.95%.Therefore,it is concluded that an increase in either or both the temperature and velocity of the injected water leads to increased oil production,which is physically realistic.This indicates that the developed model is able to give useful insights into hot water flooding.展开更多
Wind turbines play a vital role in renewable energy production.This review examines advancements in wind turbine blade morphing technologies aimed at enhancing power coefficients,reducing vibrations,andminimizing nois...Wind turbines play a vital role in renewable energy production.This review examines advancements in wind turbine blade morphing technologies aimed at enhancing power coefficients,reducing vibrations,andminimizing noise generation.Efficiency,vibration,and noise levels can be optimized through morphing techniques applied to the blade’s shape,leading edge,trailing edge,and surface.Leading-edge morphing is particularly effective in improving efficiency and reducing noise,as flow attachment and separation at the leading edge significantly influence lift and vortex generation.Morphing technologies often draw inspiration from bionic designs based on natural phenomena,highlighting the potential of biomimicry to improve aerodynamic performance and energy capture.Understanding fluid-structure interactions is critical to ensuring the lifespan,performance,and safety of wind turbine blades,which directly affect operational efficiency and noise levels.This review underscores the importance of comprehending the interdependencies between aerodynamics,vibration,and noise to guide future research and policy in sustainable wind energy development.By summarizing key advancements in the field,this paper serves as a valuable resource for researchers,policymakers,and industry leaders involved in wind energy technologies.展开更多
An experimental study of the diffusive mass transfer between a droplet and an oscillating immiscible liquid in a horizontal axisymmetricHele-Shaw cell is carried out.Theliquid oscillates radially in the cell.Thetransv...An experimental study of the diffusive mass transfer between a droplet and an oscillating immiscible liquid in a horizontal axisymmetricHele-Shaw cell is carried out.Theliquid oscillates radially in the cell.Thetransverse size of the droplet exceeds the cell thickness.The viscosities of the droplet and the surrounding liquid are comparable.Relevant effort is provided to design and test an experimental setup and validate a protocol for determining the mass transfer rate of a solute in a two-liquid system.In particular,fluorescent dye Rhodamine B is considered as the solute.A critical comparison of the situations with and without oscillation is implemented.A procedure is introduced and validated to determine the molecular and effective diffusion coefficients through evaluation of the growth of the diffusion zone width over time.It is shown that,in the presence of the liquid oscillations,there is a significant increase in the width of the zone in which Rhodamine B is present compared to the reference case with no oscillations.The oscillatory flow leads to an intensification of the solute diffusion due to intense time-averaged flows inside the droplet and the surrounding liquid and oscillations of the drop itself.Thestudy is of significant practical interest with particular relevance to typical processes for liquid-liquid extraction.展开更多
Carbon dioxide(CO_(2))is often monitored as a convenient yardstick for indoor air safety,yet its ability to stand in for pathogen-laden aerosols has never been settled.To probe the question,we reproduced an open-plan ...Carbon dioxide(CO_(2))is often monitored as a convenient yardstick for indoor air safety,yet its ability to stand in for pathogen-laden aerosols has never been settled.To probe the question,we reproduced an open-plan office at full scale(7.2m×5.2m×2.8m)and introduced a breathing plume that carried 4% CO_(2),together with a polydisperse aerosol spanning 0.5–10μm(1320 particles s^(−1)).Inlet air was supplied at 0.7,1.4,and 2.1 m s^(−1),and the resulting fields were simulated with a Realisable k–εRANS model coupled to Lagrangian particle tracking.Nine strategically placed probes provided validation;the calibrated solution deviated fromthe experiment by 58 ppm for CO_(2)(8.1%RMSE)and 0.008 m s^(−1)for velocity(15.7%RMSE).Despite this agreement,gas and particles behaved in sharply different ways.Room-averaged CO_(2)varied by<15%,whereas the aerosol mass rose to almost three-fold the background within slowmoving corner vortices.Sub-micron particles stayed aloft along streamlines,while those≥5μmpeeled away and settled on nearby surfaces.The divergence shows that neither the CO_(2)level nor themeanageof air,taken in isolation,delineates all high-exposure zones.We therefore recommend that ventilation design be informed by a composite diagnosis that couples gas data,size-resolved particle measurements,and rapid CFD appraisal.展开更多
This paper presents both analytical and numerical studies of the conservative Sawada-Kotera equation and its dissipative generalization,equations known for their soliton solutions and rich chaotic dynamics.These model...This paper presents both analytical and numerical studies of the conservative Sawada-Kotera equation and its dissipative generalization,equations known for their soliton solutions and rich chaotic dynamics.These models offer valuable insights into nonlinear wave propagation,with applications in fluid dynamics and materials science,including systems such as liquid crystals and ferrofluids.It is shown that the conservative Sawada-Kotera equation supports traveling wave solutions corresponding to elliptic limit cycles,as well as two-and three-dimensional invariant tori surrounding these cycles in the associated ordinary differential equation(ODE)system.For the dissipative generalized Sawada-Kotera equation,chaotic wave behavior is observed.The transition to chaos in the corresponding ODE systemfollows a universal bifurcation scenario consistent with the framework established by FShM(Feigenbaum-Sharkovsky-Magnitskii)theory.Notably,this study demonstrates for the first time that the conservative Sawada-Kotera equation can exhibit complex quasi-periodic wave solutions,while its dissipative counterpart admits an infinite number of stable periodic and chaotic waveforms.展开更多
This paper investigates the start-up and shutdown phases of a five-bladed closed-impeller centrifugal pump through experimental analysis,capturing the temporal evolution of its hydraulic performances.The study also pr...This paper investigates the start-up and shutdown phases of a five-bladed closed-impeller centrifugal pump through experimental analysis,capturing the temporal evolution of its hydraulic performances.The study also predicts the transient characteristics of the pump under non-rated operating conditions to assess the accuracy of various machine learning methods in forecasting its instantaneous performance.Results indicate that the pump’s transient behavior in power-frequency mode markedly differs from that in frequency-conversion mode.Specifically,the power-frequency mode achieves steady-state values faster and exhibits smaller fluctuations before stabilization compared to the other mode.During the start-up phase,as the steady-state flow rate increases,inlet and outlet pressures and head also rise,while torque and shaft power decrease,with rotational speed remaining largely unchanged.Conversely,during the shutdown phase,no significant changes were observed in torque,shaft power,or rotational speed.Six machine learning models,including Gaussian Process Regression(GPR),Decision Tree Regression(DTR),and Deep Learning Networks(DLN),demonstrated high accuracy in predicting the hydraulic performance of the centrifugal pump during the start-up and shutdown phases in both power-frequency and frequency-conversion conditions.The findings provide a theoretical foundation for improved prediction of pump hydraulic performance.For instance,when predicting head and flow rate during power-frequency start-up,GPR achieved absolute and relative errors of 0.54 m(7.84%)and 0.21 m3/h(13.57%),respectively,while the Feedforward Neural Network(FNN)reported errors of 0.98 m(8.24%)and 0.10 m3/h(16.71%).By contrast,the Support Vector Machine Regression(SVMR)and Generalized Additive Model(GAM)generally yielded less satisfactory prediction accuracy compared to the other methods.展开更多
The dynamics of fluid and non-buoyant particles in a librating horizontal annulus is studied experimentally.In the absence of librations,the granular material forms a cylindrical layer near the outer boundary of the a...The dynamics of fluid and non-buoyant particles in a librating horizontal annulus is studied experimentally.In the absence of librations,the granular material forms a cylindrical layer near the outer boundary of the annulus and undergoes rigid-body rotation with the fluid and the annulus.It is demonstrated that the librational liquefaction of the granular material results in pattern formation.This self-organization process stems from the excitation of inertial modes induced by the oscillatory motion of liquefied granular material under the influence of the gravitational force.The inertial wave induces vortical fluid flow which entrains particles from rest and forms eroded areas that are equidistant from each other along the axis of rotation.Theoretical analysis and experiments demonstrate that a liquefied layer of granular material oscillates with a radian frequency equal to the angular velocity of the annulus and interacts with the inertial wave it excites.The new phenomenon of libration-induced pattern formation is of practical interest as it can be used to control multiphase flows and mass transfer in rotating containers in a variety of industrial processes.展开更多
In modern engineering,enhancing boiling heat transfer efficiency is crucial for optimizing energy use and several industrial processes involving different types of materials.This study explores the enhancement of pool...In modern engineering,enhancing boiling heat transfer efficiency is crucial for optimizing energy use and several industrial processes involving different types of materials.This study explores the enhancement of pool boiling heat transfer potentially induced by combining perforated copper particles on a heated surface with a sodium dodecyl sulfate(SDS)surfactant in saturated deionized water.Experiments were conducted at standard atmospheric pressure,with heat flux ranging from 20 to 100 kW/m2.The heating surface,positioned below the layer of freely moving copper beads,allowed the particle layer to shift due to liquid convection and steam nucleation.The study reports on the influence of copper bead diameter(2,3,4,and 5 mm),particle quantity,arrangement,and SDS concentration(20,200,and 500 ppm).It is shown that the combination of 5 mm particles and a 500 ppm SDS concentration can yield a remarkable 139%improvement in heat transfer efficiency.As demonstrated by direct flow visualization,bubble formation occurs primarily in the gaps between the particles and the heated surface,with the presence of SDS reducing bubble size and accelerating bubble detachment.展开更多
This study introduces a Transformer-based multimodal fusion framework for simulating multiphase flow and heat transfer in carbon dioxide(CO_(2))–water enhanced geothermal systems(EGS).The model integrates geological ...This study introduces a Transformer-based multimodal fusion framework for simulating multiphase flow and heat transfer in carbon dioxide(CO_(2))–water enhanced geothermal systems(EGS).The model integrates geological parameters,thermal gradients,and control schedules to enable fast and accurate prediction of complex reservoir dynamics.The main contributions are:(i)development of a workflow that couples physics-based reservoir simulation with a Transformer neural network architecture,(ii)design of physics-guided loss functions to enforce conservation of mass and energy,(iii)application of the surrogate model to closed-loop optimization using a differential evolution(DE)algorithm,and(iv)incorporation of economic performance metrics,such as net present value(NPV),into decision support.The proposed framework achieves root mean square error(RMSE)of 3–5%,mean absolute error(MAE)below 4%,and coefficients of determination greater than 0.95 across multiple prediction targets,including production rates,pressure distributions,and temperature fields.When compared with recurrent neural network(RNN)baselines such as gated recurrent units(GRU)and long short-term memory networks(LSTM),as well as a physics-informed reduced-order model,the Transformer-based approach demonstrates superior accuracy and computational efficiency.Optimization experiments further show a 15–20%improvement in NPV,highlighting the framework’s potential for real-time forecasting,optimization,and decision-making in geothermal reservoir engineering.展开更多
In recent years,tuned liquid dampers(TLDs)have emerged as a focal point of research due to their remarkable potential for structural vibration mitigation.Yet,progress in this field remains constrained by an incomplete...In recent years,tuned liquid dampers(TLDs)have emerged as a focal point of research due to their remarkable potential for structural vibration mitigation.Yet,progress in this field remains constrained by an incomplete understanding of the fundamental mechanisms governing sloshing-induced loads in liquid-filled containers.Aqueducts present a distinctive case,as the capacity of their contained water to function effectively as a TLD remains uncertain.To address this gap,the present study investigates the generation mechanisms of sloshing loads under non-resonant cases through a two-dimensional(2D)computational fluid dynamics(CFD)model developed in ANSYS Fluent.The incompressible Reynolds-Averaged Navier–Stokes(RANS)equations are solved,while the Volume of Fluid(VOF)method captures the evolution of the air–water interface.Turbulent flow behavior is modeled using the RNG-approach.The ensuing results reveal the dynamic characteristics of the horizontal force(fℎ)and the fluctuating component of the vertical force(Fof).Fh is predominantly governed by the inertia of the deep-water region and its phase varies coherently with the aqueduct’s acceleration.With increasing excitation amplitude(A)and frequency(f),the contribution of deep-water inertia to𝐹ℎintensifies markedly,accounting for 82.6–92.1%of the total horizontal load at an excitation amplitude of 0.15 m and frequencies of 1.0–1.6 Hz.The extreme values of Fof arise primarily from asymmetric static pressures induced by free-surface fluctuations,which are further amplified when wall gaps appear at large amplitudes(A≥10 cm)and high frequencies(f≥1.4 Hz).Unlike resonant cases dominated by free-surface resonance,non-resonant sloshing loads are principally driven by deep-water inertia and motion-induced surface asymmetry.展开更多
Condensate gas reservoirs have attracted increasing attention in recent years due to their significant development potential and dual value from both natural gas and condensate oil.However,their exploitation is often ...Condensate gas reservoirs have attracted increasing attention in recent years due to their significant development potential and dual value from both natural gas and condensate oil.However,their exploitation is often hindered by the dual challenges of retrograde condensation and water invasion,which can markedly reduce recovery factors.CO_(2) injection offers a promising solution by alleviating condensate blockage,suppressing water influx,and simultaneously enabling geological CO_(2) storage.Accordingly,research on optimizing CO_(2) injection to mitigate formation damage is critical for the efficient development and management of edge-and bottom-water condensate gas reservoirs.In this study,a long-core displacement mechanism model was constructed using CMG-GEMTM andWinPropTM.The model simulates reservoir depletion from initial conditions(41.2 MPa,102.5℃)to the current reservoir pressure(13.5 MPa),followed by gas injection.It was then upscaled to the edge-and bottom-water reservoir scale to capture complex fluid phase behavior,enabling a multi-factor coupled optimization of CO_(2) injection strategies.Model reliability was verified through comparison with core experimental results.Subsequently,the effects of geological parameters(e.g.,reservoir permeability and rhythmic heterogeneity)and engineering parameters(e.g.,injection pressure and rate)on reservoir performance were systematically evaluated.The results indicate that appropriate target zone selection and optimization of injection pressure and rate—avoiding formation fracturing and preventing gas channeling—can substantially improve reservoir development outcomes.Applying this approach to the K Gas Reservoir,the optimal strategy involved injecting CO_(2) at a rate of 5×10^(4) m^(3)/d,restoring pressure to 22.5 MPa in a composite rhythmic reservoir with an average permeability of 10 mD.This scheme increased the condensate oil recovery factor by 18.7 percentage points(from 43.9%to 60.9%)while reducing the water-cut rise rate by approximately 34%.展开更多
The present review explores the promising role of nanofluids and related hybrid variants in enhancing the efficiencyof flat tube car radiators.As vehicles become more advanced and demand better thermal performance,tra...The present review explores the promising role of nanofluids and related hybrid variants in enhancing the efficiencyof flat tube car radiators.As vehicles become more advanced and demand better thermal performance,traditional coolants are starting to fall short.Nanofluids,which involve tiny nanoparticles dispersed into standardcooling liquids,offer a new solution by significantly improving heat transfer capabilities.The article categorizesthe different types of nanofluids(ranging from those based on metals and metal oxides to carbon materials andhybrid combinations)and examines their effects on the improvement of radiator performance.General consensusexists in the literature that nanofluids can support better heat dissipation and enable accordingly the developmentof smaller and lighter radiators,which require less coolant and allow more compact vehicle designs.However,thisreview demonstrates that the use of nanofluids does not come without challenges.These include the long-termstability of these fluids and material compatibility issues.A critical discussion is therefore elaborated about thegaps to be filled and the steps to be undertaken to promote and standardize the use of these fluids in the industry.展开更多
A precise diagnosis of the complex post-fracturing characteristics and parameter variations in tight gas reservoirs is essential for optimizing fracturing technology,enhancing treatment effectiveness,and assessing pos...A precise diagnosis of the complex post-fracturing characteristics and parameter variations in tight gas reservoirs is essential for optimizing fracturing technology,enhancing treatment effectiveness,and assessing post-fracturing production capacity.Tight gas reservoirs face challenges due to the interaction between natural fractures and induced fractures.To address these issues,a theoretical model for diagnosing fractures under varying leak-off mechanisms has been developed,incorporating the closure behavior of natural fractures.This model,grounded in material balance theory,also accounts for shut-in pressure.The study derived and plotted typical G-function charts,which capture fracture behavior during closure.By superimposing the G-function in the closure phase of natural fractures with pressure derivative curves,the study explored how fracture parameters—including leak-off coefficient,fracture area,closure pressure,and closure time—impact these diagnostic charts.Findings show that variations in natural fracture flexibility,fracture area,and controlling factors influence the superimposed G-function pressure derivative curve,resulting in distinctive“concave”or“convex”patterns.Field data from Well Y in a specific tight gas reservoir were used to validate the model,confirming both its reliability and practicality.展开更多
Thermal vibrational convection(TVC)refers to the time-averaged convection of a non-isothermal fluid subjected to oscillating force fields.It serves as an effective mechanism for heat transfer control,particularly unde...Thermal vibrational convection(TVC)refers to the time-averaged convection of a non-isothermal fluid subjected to oscillating force fields.It serves as an effective mechanism for heat transfer control,particularly under microgravity conditions.A key challenge in this field is understanding the effect of rotation on TVC,as fluid oscillations in rotating systems exhibit unique and specific characteristics.In this study,we examine TVC in a vertical flat layer with boundaries at different temperatures,rotating around a horizontal axis.The distinctive feature of this study is that the fluid oscillations within the cavity are not induced by vibrations of the cavity itself,but rather by the gravity field,giving them a tidal nature.Our findings reveal that inertial waves generated in the rotating layer qualitatively alter the TVC structure,producing time-averaged flows in the form of toroidal vortices.Experimental investigations of the structure of oscillatory and time-averaged flows,conducted using Particle Image Velocimetry(PIV)for flow velocity visualization,are complemented by theoretical calculations of inertial modes in a cavity with this geometry.To the best of our knowledge,this study represents the first of its kind.The agreement between experimental results and theoretical predictions confirms that the formation of convective structures in the form of toroidal vortices is driven by inertial waves induced by the gravity field.A decrease in the rotational velocity leads to a transformation of the convective structures,shifting from toroidal vortices of inertial-wave origin to classical cellular TVC.We present dimensionless parameters that define the excitation thresholds for both cellular convection and toroidal structures.展开更多
This study investigates the unsteady flow characteristics of shale oil reservoirs during the depletion development process,with a particular focus on production behavior following fracturing and shut-in stages.Shale r...This study investigates the unsteady flow characteristics of shale oil reservoirs during the depletion development process,with a particular focus on production behavior following fracturing and shut-in stages.Shale reservoirs exhibit distinctive production patterns that differ from traditional oil reservoirs,as their inflow performance does not conform to the classic steady-state relationship.Instead,production is governed by unsteady-state flow behavior,and the combined effects of thewellbore and choke cause the inflowperformance curve to evolve dynamically over time.To address these challenges,this study introduces the concept of a“Dynamic IPR curve”and develops a dynamic production analysis method that integrates production time,continuity across multi-stage state fields,and the interactions between tubing flow and choke flow.This method provides a robust framework to characterize the attenuation trend of reservoir productivity and to accurately describe wellbore flow behavior.By applying the dynamic IPR approach,the study overcomes the limitations of conventional methods,which are unable to capture the temporal variations inherent in shale reservoir production.The proposed methodology offers a theoretical foundation for improved production forecasting,optimization of choke size,and analysis of wellbore tubing characteristics,thereby supporting more effective operational decision-making across different stages of shale reservoir development.展开更多
文摘Hydrodynamic cavitation,as an efficient technique applied in many physical and chemical treatment methods,has been widely used by various industries and in several technological fields.Relevant generators,designed with specific structures and parameters,can produce cavitation effects,thereby enabling effective treatment and reasonable transformation of substances.This paper reviews the design principles,performance,and practical applications associated with different types of cavitation generators,aiming to provide theoretical support for the optimization of these systems.It systematically analyzes the underpinning mechanisms and the various factors influencing the cavitation phenomena,also conducting a comparative analysis of the performance of different types of generators.Specific applications dealing with wastewater treatment,chemical reaction acceleration,and other fields are discussed together with the advantages,disadvantages,and applicability of each type of cavitation generator.We also explore research progress in areas such as cavitation stability,energy efficiency,and equipment design upgrades.The study concludes by forecasting the application prospects of intelligent design and computational fluid dynamics(CFD)in optimizing and advancing cavitation generators.It proposes new ideas for the further development of cavitation technology and highlights directions for its widespread future application.
文摘The objective of this study is to propose an optimal plant design for blue hydrogen production aboard a liquefiednatural gas(LNG)carrier.This investigation focuses on integrating two distinct processes—steam methanereforming(SMR)and ship-based carbon capture(SBCC).The first refers to the common practice used to obtainhydrogen from methane(often derived from natural gas),where steam reacts with methane to produce hydrogenand carbon dioxide(CO_(2)).The second refers to capturing the CO_(2) generated during the SMR process on boardships.By capturing and storing the carbon emissions,the process significantly reduces its environmental impact,making the hydrogen production“blue,”as opposed to“grey”(which involves CO_(2) emissions without capture).For the SMR process,the analysis reveals that increasing the reformer temperature enhances both the processperformance and CO_(2) emissions.Conversely,a higher steam-to-carbon(s/c)ratio reduces hydrogen yield,therebydecreasing thermal efficiency.The study also shows that preheating the air and boil-off gas(BOG)before theyenter the combustion chamber boosts overall efficiency and curtails CO_(2) emissions.In the SBCC process,puremonoethanolamine(MEA)is employed to capture the CO_(2) generated by the exhaust gases from the SMR process.The results indicate that with a 90%CO_(2) capture rate,the associated heat consumption amounts to 4.6 MJ perkilogram of CO_(2) captured.This combined approach offers a viable pathway to produce blue hydrogen on LNGcarriers while significantly reducing the carbon footprint.
文摘This paper aims to numerically explore the characteristics of unsteady cavitating flow around a NACA0015 hydrofoil,with a focus on vorticity attributes.The simulation utilizes a homogeneous mixture model coupled with a filter-based density correction turbulence model and a modified Zwart cavitation model.The study investigates the dynamic cavitation features of the thermal fluid around the hydrofoil at various incoming flow velocities.It systematically elucidates the evolution of cavitation and vortex dynamics corresponding to each velocity condition.The results indicate that with increasing incoming flow velocity,distinct cavitation processes take place in the flow field.
基金supported by the National Natural Science Foundation of China(52365056).
文摘Ultra-precision components have been widely used to produce advanced optoelectronic equipment.The so-called Electric field enhanced UltraViolet-Induced Jet Machining(EUV-INCJM)is an ultra-precision method that can achieve sub-nanometer level surface quality polishing.This study focuses on the application of the EUV-INCJM with different nozzle structures to a single-crystal of silicon.Two kinds of electro-optic-liquid coupling nozzles with single-jet and multi-jet focusing structures are proposed accordingly.Simulations and experiments have been conducted to verify the material removal performance of these nozzles.The simulation results show that,under the same condition,the flow velocity of the single-jet nozzle is 1.05 times higher than that achieved with the multi-jet configuration,while the current density of the latter is 1.63 times higher than that of the single-jet nozzle.For the single-crystal silicon,the material removal efficiency of the multi-jet focusing nozzle exceeds by about 1.4 times that of the single-jet.These results confirm that the material removal ability of the multi-jet configuration is more suitable for ultra-smooth surface polishing.The surface roughness of Si workpiece was reduced from Rq 1.55 to Rq 0.816 nm with valleys and peaks on its surface being almost completely removed.
文摘Understanding the complex interaction between heat and mass transfer in non-Newtonian microflows is essential for the development and optimization of efficient microfluidic and thermal management systems.This study investigates the magnetohydrodynamic(MHD)thermosolutal convection of a Casson fluid within an inclined,porous microchannel subjected to convective boundary conditions.The nonlinear,coupled equations governing momentum,energy,and species transport are solved numerically using the MATLAB bvp4c solver,ensuring high numerical accuracy and stability.To identify the dominant parameters influencing flow behavior and to optimize transport performance,a comprehensive hybrid optimization framework—combining a modified Taguchi design,Grey Relational Analysis(GRA),and Principal Component Analysis(PCA)—is proposed.This integrated strategy enables the simultaneous assessment of skin friction,Nusselt number,and Sherwood number,providing a rigorous multi-objective evaluation of system performance.Comparative validation with benchmark results from the literature confirms the accuracy and reliability of the present formulation and its numerical implementation.The results highlight the intricate coupling among flow slip,buoyancy effects,and convective transport mechanisms.Increased slip flow enhances axial velocity,while a higher solutal Biot number intensifies concentration gradients near the channel walls.Conversely,a lower thermal Biot number diminishes the temperature field,indicating weaker heat transfer across the boundaries.PCA results reveal that the first principal component(PC1)accounts for most of the system variance,demonstrating the dominant influence of coupled flow and transport parameters on overall system performance.
文摘In the early stages of oil exploration,oil is produced through processes such as well drilling.Later,hot water may be injected into the well to improve production.A key challenge is understanding how the temperature and velocity of the injected hot water affect the production rate.This is the focus of the current study.It proposes variableviscosity mathematical models for heat and water saturation in a reservoir containing Bonny-light crude oil,with the aim of investigating the effects of water temperature and velocity on the recovery rate.First,two sets of experimental data are used to construct explicit temperature-dependent viscosity models for Bonny-light crude oil and water.These viscosity models are incorporated into the Buckley-Leverette equation for the dynamics of water saturation.A convex combination of the thermal conductivities of oil and water is used to formulate a heat propagation model.A finite volume scheme with temperature-dependent HLL numerical flux is proposed for saturation,while a finite difference approximation is derived for the heat model,both on a staggered grid.The convergence of the method is verified numerically.Simulations are conducted with different parameter values.The results show that at a wall temperature of 10℃,an increase in the injection velocity from 0.1 to 0.25 increases the production rate from 8.33%to 20.8%.Meanwhile,with an injection velocity of v=1,an increase in the temperature of the injected water from 25℃ to 55℃ increases production rate from 59.48%to 61.95%.Therefore,it is concluded that an increase in either or both the temperature and velocity of the injected water leads to increased oil production,which is physically realistic.This indicates that the developed model is able to give useful insights into hot water flooding.
文摘Wind turbines play a vital role in renewable energy production.This review examines advancements in wind turbine blade morphing technologies aimed at enhancing power coefficients,reducing vibrations,andminimizing noise generation.Efficiency,vibration,and noise levels can be optimized through morphing techniques applied to the blade’s shape,leading edge,trailing edge,and surface.Leading-edge morphing is particularly effective in improving efficiency and reducing noise,as flow attachment and separation at the leading edge significantly influence lift and vortex generation.Morphing technologies often draw inspiration from bionic designs based on natural phenomena,highlighting the potential of biomimicry to improve aerodynamic performance and energy capture.Understanding fluid-structure interactions is critical to ensuring the lifespan,performance,and safety of wind turbine blades,which directly affect operational efficiency and noise levels.This review underscores the importance of comprehending the interdependencies between aerodynamics,vibration,and noise to guide future research and policy in sustainable wind energy development.By summarizing key advancements in the field,this paper serves as a valuable resource for researchers,policymakers,and industry leaders involved in wind energy technologies.
基金supported by the Russian Science Foundation(Grant No.23-11-00242).
文摘An experimental study of the diffusive mass transfer between a droplet and an oscillating immiscible liquid in a horizontal axisymmetricHele-Shaw cell is carried out.Theliquid oscillates radially in the cell.Thetransverse size of the droplet exceeds the cell thickness.The viscosities of the droplet and the surrounding liquid are comparable.Relevant effort is provided to design and test an experimental setup and validate a protocol for determining the mass transfer rate of a solute in a two-liquid system.In particular,fluorescent dye Rhodamine B is considered as the solute.A critical comparison of the situations with and without oscillation is implemented.A procedure is introduced and validated to determine the molecular and effective diffusion coefficients through evaluation of the growth of the diffusion zone width over time.It is shown that,in the presence of the liquid oscillations,there is a significant increase in the width of the zone in which Rhodamine B is present compared to the reference case with no oscillations.The oscillatory flow leads to an intensification of the solute diffusion due to intense time-averaged flows inside the droplet and the surrounding liquid and oscillations of the drop itself.Thestudy is of significant practical interest with particular relevance to typical processes for liquid-liquid extraction.
文摘Carbon dioxide(CO_(2))is often monitored as a convenient yardstick for indoor air safety,yet its ability to stand in for pathogen-laden aerosols has never been settled.To probe the question,we reproduced an open-plan office at full scale(7.2m×5.2m×2.8m)and introduced a breathing plume that carried 4% CO_(2),together with a polydisperse aerosol spanning 0.5–10μm(1320 particles s^(−1)).Inlet air was supplied at 0.7,1.4,and 2.1 m s^(−1),and the resulting fields were simulated with a Realisable k–εRANS model coupled to Lagrangian particle tracking.Nine strategically placed probes provided validation;the calibrated solution deviated fromthe experiment by 58 ppm for CO_(2)(8.1%RMSE)and 0.008 m s^(−1)for velocity(15.7%RMSE).Despite this agreement,gas and particles behaved in sharply different ways.Room-averaged CO_(2)varied by<15%,whereas the aerosol mass rose to almost three-fold the background within slowmoving corner vortices.Sub-micron particles stayed aloft along streamlines,while those≥5μmpeeled away and settled on nearby surfaces.The divergence shows that neither the CO_(2)level nor themeanageof air,taken in isolation,delineates all high-exposure zones.We therefore recommend that ventilation design be informed by a composite diagnosis that couples gas data,size-resolved particle measurements,and rapid CFD appraisal.
文摘This paper presents both analytical and numerical studies of the conservative Sawada-Kotera equation and its dissipative generalization,equations known for their soliton solutions and rich chaotic dynamics.These models offer valuable insights into nonlinear wave propagation,with applications in fluid dynamics and materials science,including systems such as liquid crystals and ferrofluids.It is shown that the conservative Sawada-Kotera equation supports traveling wave solutions corresponding to elliptic limit cycles,as well as two-and three-dimensional invariant tori surrounding these cycles in the associated ordinary differential equation(ODE)system.For the dissipative generalized Sawada-Kotera equation,chaotic wave behavior is observed.The transition to chaos in the corresponding ODE systemfollows a universal bifurcation scenario consistent with the framework established by FShM(Feigenbaum-Sharkovsky-Magnitskii)theory.Notably,this study demonstrates for the first time that the conservative Sawada-Kotera equation can exhibit complex quasi-periodic wave solutions,while its dissipative counterpart admits an infinite number of stable periodic and chaotic waveforms.
基金financially supported by Science and Technology Project of Quzhou(Grant Nos.2023K256,2023NC08)Research Grants Program of Department of Education of Zhejiang Province(No.Y202455709)+1 种基金Zhejiang Provincial Natural Science Foundation of China(Grant No.LZY21E050001)University-Enterprise Cooperation Program for Visiting Engineers in Higher Education Institutions in Zhejiang Province(No.FG2020215).
文摘This paper investigates the start-up and shutdown phases of a five-bladed closed-impeller centrifugal pump through experimental analysis,capturing the temporal evolution of its hydraulic performances.The study also predicts the transient characteristics of the pump under non-rated operating conditions to assess the accuracy of various machine learning methods in forecasting its instantaneous performance.Results indicate that the pump’s transient behavior in power-frequency mode markedly differs from that in frequency-conversion mode.Specifically,the power-frequency mode achieves steady-state values faster and exhibits smaller fluctuations before stabilization compared to the other mode.During the start-up phase,as the steady-state flow rate increases,inlet and outlet pressures and head also rise,while torque and shaft power decrease,with rotational speed remaining largely unchanged.Conversely,during the shutdown phase,no significant changes were observed in torque,shaft power,or rotational speed.Six machine learning models,including Gaussian Process Regression(GPR),Decision Tree Regression(DTR),and Deep Learning Networks(DLN),demonstrated high accuracy in predicting the hydraulic performance of the centrifugal pump during the start-up and shutdown phases in both power-frequency and frequency-conversion conditions.The findings provide a theoretical foundation for improved prediction of pump hydraulic performance.For instance,when predicting head and flow rate during power-frequency start-up,GPR achieved absolute and relative errors of 0.54 m(7.84%)and 0.21 m3/h(13.57%),respectively,while the Feedforward Neural Network(FNN)reported errors of 0.98 m(8.24%)and 0.10 m3/h(16.71%).By contrast,the Support Vector Machine Regression(SVMR)and Generalized Additive Model(GAM)generally yielded less satisfactory prediction accuracy compared to the other methods.
基金funded by the Ministry of Education of the Russian Federation within the framework of a state assignment,number 1023032300071-6-2.3.1.
文摘The dynamics of fluid and non-buoyant particles in a librating horizontal annulus is studied experimentally.In the absence of librations,the granular material forms a cylindrical layer near the outer boundary of the annulus and undergoes rigid-body rotation with the fluid and the annulus.It is demonstrated that the librational liquefaction of the granular material results in pattern formation.This self-organization process stems from the excitation of inertial modes induced by the oscillatory motion of liquefied granular material under the influence of the gravitational force.The inertial wave induces vortical fluid flow which entrains particles from rest and forms eroded areas that are equidistant from each other along the axis of rotation.Theoretical analysis and experiments demonstrate that a liquefied layer of granular material oscillates with a radian frequency equal to the angular velocity of the annulus and interacts with the inertial wave it excites.The new phenomenon of libration-induced pattern formation is of practical interest as it can be used to control multiphase flows and mass transfer in rotating containers in a variety of industrial processes.
基金supported by the National Natural Science Foundation of China(Project No.52166004)the National Key Research and Development Program of China(Project No.2022YFC3902000)+2 种基金the Major Science and Technology Special Project of Yunnan Province(Project Nos.202202AG050007202202AG050002)the Research on the Development of Complete Sets of Technology for Extraction of Aromatic Substances from Tobacco Waste and Its Application,Applied Research-Pyrolysis Process Technology Research(2023QT01).
文摘In modern engineering,enhancing boiling heat transfer efficiency is crucial for optimizing energy use and several industrial processes involving different types of materials.This study explores the enhancement of pool boiling heat transfer potentially induced by combining perforated copper particles on a heated surface with a sodium dodecyl sulfate(SDS)surfactant in saturated deionized water.Experiments were conducted at standard atmospheric pressure,with heat flux ranging from 20 to 100 kW/m2.The heating surface,positioned below the layer of freely moving copper beads,allowed the particle layer to shift due to liquid convection and steam nucleation.The study reports on the influence of copper bead diameter(2,3,4,and 5 mm),particle quantity,arrangement,and SDS concentration(20,200,and 500 ppm).It is shown that the combination of 5 mm particles and a 500 ppm SDS concentration can yield a remarkable 139%improvement in heat transfer efficiency.As demonstrated by direct flow visualization,bubble formation occurs primarily in the gaps between the particles and the heated surface,with the presence of SDS reducing bubble size and accelerating bubble detachment.
文摘This study introduces a Transformer-based multimodal fusion framework for simulating multiphase flow and heat transfer in carbon dioxide(CO_(2))–water enhanced geothermal systems(EGS).The model integrates geological parameters,thermal gradients,and control schedules to enable fast and accurate prediction of complex reservoir dynamics.The main contributions are:(i)development of a workflow that couples physics-based reservoir simulation with a Transformer neural network architecture,(ii)design of physics-guided loss functions to enforce conservation of mass and energy,(iii)application of the surrogate model to closed-loop optimization using a differential evolution(DE)algorithm,and(iv)incorporation of economic performance metrics,such as net present value(NPV),into decision support.The proposed framework achieves root mean square error(RMSE)of 3–5%,mean absolute error(MAE)below 4%,and coefficients of determination greater than 0.95 across multiple prediction targets,including production rates,pressure distributions,and temperature fields.When compared with recurrent neural network(RNN)baselines such as gated recurrent units(GRU)and long short-term memory networks(LSTM),as well as a physics-informed reduced-order model,the Transformer-based approach demonstrates superior accuracy and computational efficiency.Optimization experiments further show a 15–20%improvement in NPV,highlighting the framework’s potential for real-time forecasting,optimization,and decision-making in geothermal reservoir engineering.
基金supported by Science and Technology Planning Project of Sichuan Province with Grant No.2023YFS0429supported by Science and Technology Project of China Road and Bridge Corporation with Grant No.P2220447+1 种基金supported by Foundation of Xinjiang Institute of Engineering 2024(Grant No.2024xgy072605)also supported by Sichuan Natural Science Foundation Project(Grant No.2024NSFSC0162).
文摘In recent years,tuned liquid dampers(TLDs)have emerged as a focal point of research due to their remarkable potential for structural vibration mitigation.Yet,progress in this field remains constrained by an incomplete understanding of the fundamental mechanisms governing sloshing-induced loads in liquid-filled containers.Aqueducts present a distinctive case,as the capacity of their contained water to function effectively as a TLD remains uncertain.To address this gap,the present study investigates the generation mechanisms of sloshing loads under non-resonant cases through a two-dimensional(2D)computational fluid dynamics(CFD)model developed in ANSYS Fluent.The incompressible Reynolds-Averaged Navier–Stokes(RANS)equations are solved,while the Volume of Fluid(VOF)method captures the evolution of the air–water interface.Turbulent flow behavior is modeled using the RNG-approach.The ensuing results reveal the dynamic characteristics of the horizontal force(fℎ)and the fluctuating component of the vertical force(Fof).Fh is predominantly governed by the inertia of the deep-water region and its phase varies coherently with the aqueduct’s acceleration.With increasing excitation amplitude(A)and frequency(f),the contribution of deep-water inertia to𝐹ℎintensifies markedly,accounting for 82.6–92.1%of the total horizontal load at an excitation amplitude of 0.15 m and frequencies of 1.0–1.6 Hz.The extreme values of Fof arise primarily from asymmetric static pressures induced by free-surface fluctuations,which are further amplified when wall gaps appear at large amplitudes(A≥10 cm)and high frequencies(f≥1.4 Hz).Unlike resonant cases dominated by free-surface resonance,non-resonant sloshing loads are principally driven by deep-water inertia and motion-induced surface asymmetry.
基金supported by the National Natural Science Foundation of China(No.52474047).
文摘Condensate gas reservoirs have attracted increasing attention in recent years due to their significant development potential and dual value from both natural gas and condensate oil.However,their exploitation is often hindered by the dual challenges of retrograde condensation and water invasion,which can markedly reduce recovery factors.CO_(2) injection offers a promising solution by alleviating condensate blockage,suppressing water influx,and simultaneously enabling geological CO_(2) storage.Accordingly,research on optimizing CO_(2) injection to mitigate formation damage is critical for the efficient development and management of edge-and bottom-water condensate gas reservoirs.In this study,a long-core displacement mechanism model was constructed using CMG-GEMTM andWinPropTM.The model simulates reservoir depletion from initial conditions(41.2 MPa,102.5℃)to the current reservoir pressure(13.5 MPa),followed by gas injection.It was then upscaled to the edge-and bottom-water reservoir scale to capture complex fluid phase behavior,enabling a multi-factor coupled optimization of CO_(2) injection strategies.Model reliability was verified through comparison with core experimental results.Subsequently,the effects of geological parameters(e.g.,reservoir permeability and rhythmic heterogeneity)and engineering parameters(e.g.,injection pressure and rate)on reservoir performance were systematically evaluated.The results indicate that appropriate target zone selection and optimization of injection pressure and rate—avoiding formation fracturing and preventing gas channeling—can substantially improve reservoir development outcomes.Applying this approach to the K Gas Reservoir,the optimal strategy involved injecting CO_(2) at a rate of 5×10^(4) m^(3)/d,restoring pressure to 22.5 MPa in a composite rhythmic reservoir with an average permeability of 10 mD.This scheme increased the condensate oil recovery factor by 18.7 percentage points(from 43.9%to 60.9%)while reducing the water-cut rise rate by approximately 34%.
文摘The present review explores the promising role of nanofluids and related hybrid variants in enhancing the efficiencyof flat tube car radiators.As vehicles become more advanced and demand better thermal performance,traditional coolants are starting to fall short.Nanofluids,which involve tiny nanoparticles dispersed into standardcooling liquids,offer a new solution by significantly improving heat transfer capabilities.The article categorizesthe different types of nanofluids(ranging from those based on metals and metal oxides to carbon materials andhybrid combinations)and examines their effects on the improvement of radiator performance.General consensusexists in the literature that nanofluids can support better heat dissipation and enable accordingly the developmentof smaller and lighter radiators,which require less coolant and allow more compact vehicle designs.However,thisreview demonstrates that the use of nanofluids does not come without challenges.These include the long-termstability of these fluids and material compatibility issues.A critical discussion is therefore elaborated about thegaps to be filled and the steps to be undertaken to promote and standardize the use of these fluids in the industry.
文摘A precise diagnosis of the complex post-fracturing characteristics and parameter variations in tight gas reservoirs is essential for optimizing fracturing technology,enhancing treatment effectiveness,and assessing post-fracturing production capacity.Tight gas reservoirs face challenges due to the interaction between natural fractures and induced fractures.To address these issues,a theoretical model for diagnosing fractures under varying leak-off mechanisms has been developed,incorporating the closure behavior of natural fractures.This model,grounded in material balance theory,also accounts for shut-in pressure.The study derived and plotted typical G-function charts,which capture fracture behavior during closure.By superimposing the G-function in the closure phase of natural fractures with pressure derivative curves,the study explored how fracture parameters—including leak-off coefficient,fracture area,closure pressure,and closure time—impact these diagnostic charts.Findings show that variations in natural fracture flexibility,fracture area,and controlling factors influence the superimposed G-function pressure derivative curve,resulting in distinctive“concave”or“convex”patterns.Field data from Well Y in a specific tight gas reservoir were used to validate the model,confirming both its reliability and practicality.
基金funded by the Ministry of Education of the Russian Federation within the framework of a state assignment,number 1023032300071-6-2.3.1.
文摘Thermal vibrational convection(TVC)refers to the time-averaged convection of a non-isothermal fluid subjected to oscillating force fields.It serves as an effective mechanism for heat transfer control,particularly under microgravity conditions.A key challenge in this field is understanding the effect of rotation on TVC,as fluid oscillations in rotating systems exhibit unique and specific characteristics.In this study,we examine TVC in a vertical flat layer with boundaries at different temperatures,rotating around a horizontal axis.The distinctive feature of this study is that the fluid oscillations within the cavity are not induced by vibrations of the cavity itself,but rather by the gravity field,giving them a tidal nature.Our findings reveal that inertial waves generated in the rotating layer qualitatively alter the TVC structure,producing time-averaged flows in the form of toroidal vortices.Experimental investigations of the structure of oscillatory and time-averaged flows,conducted using Particle Image Velocimetry(PIV)for flow velocity visualization,are complemented by theoretical calculations of inertial modes in a cavity with this geometry.To the best of our knowledge,this study represents the first of its kind.The agreement between experimental results and theoretical predictions confirms that the formation of convective structures in the form of toroidal vortices is driven by inertial waves induced by the gravity field.A decrease in the rotational velocity leads to a transformation of the convective structures,shifting from toroidal vortices of inertial-wave origin to classical cellular TVC.We present dimensionless parameters that define the excitation thresholds for both cellular convection and toroidal structures.
基金supported by National Natural Science Foundation of China(Grant No.52474029)National Natural Science Foundation for Young Scientists of China(A)(Grant No.52525403)+2 种基金National Major Science and Technology Projects under the 14th Five-Year Plan(Grant No.2024ZD1405105)Science and Technology Innovation Team Project of Xinjiang Uygur Autonomous Region(Grant No.2024TSYCTD0018)Xinjiang Uygur Autonomous Region.
文摘This study investigates the unsteady flow characteristics of shale oil reservoirs during the depletion development process,with a particular focus on production behavior following fracturing and shut-in stages.Shale reservoirs exhibit distinctive production patterns that differ from traditional oil reservoirs,as their inflow performance does not conform to the classic steady-state relationship.Instead,production is governed by unsteady-state flow behavior,and the combined effects of thewellbore and choke cause the inflowperformance curve to evolve dynamically over time.To address these challenges,this study introduces the concept of a“Dynamic IPR curve”and develops a dynamic production analysis method that integrates production time,continuity across multi-stage state fields,and the interactions between tubing flow and choke flow.This method provides a robust framework to characterize the attenuation trend of reservoir productivity and to accurately describe wellbore flow behavior.By applying the dynamic IPR approach,the study overcomes the limitations of conventional methods,which are unable to capture the temporal variations inherent in shale reservoir production.The proposed methodology offers a theoretical foundation for improved production forecasting,optimization of choke size,and analysis of wellbore tubing characteristics,thereby supporting more effective operational decision-making across different stages of shale reservoir development.
