The main purpose of this study is to survey numerically comparison of two- phase and single phase of heat transfer and flow field of copper-water nanofluid in a wavy channel. The computational fluid dynamics （CFD） p...The main purpose of this study is to survey numerically comparison of two- phase and single phase of heat transfer and flow field of copper-water nanofluid in a wavy channel. The computational fluid dynamics （CFD） prediction is used for heat transfer and flow prediction of the single phase and three different two-phase models （mixture, volume of fluid （VOF）, and Eulerian）. The heat transfer coefficient, temperature, and velocity distributions are investigated. The results show that the differences between the temperature fie].d in the single phase and two-phase models are greater than those in the hydrodynamic tleld. Also, it is found that the heat transfer coefficient predicted by the single phase model is enhanced by increasing the volume fraction of nanoparticles for all Reynolds numbers; while for the two-phase models, when the Reynolds number is low, increasing the volume fraction of nanoparticles will enhance the heat transfer coefficient in the front and the middle of the wavy channel, but gradually decrease along the wavy channel.展开更多
In this work, we obtain the global existence and uniqueness of classical solu-tions to a viscous liquid-gas two-phase model with mass-dependent viscosity and vacuum in one dimension, where the initial vacuum is allowe...In this work, we obtain the global existence and uniqueness of classical solu-tions to a viscous liquid-gas two-phase model with mass-dependent viscosity and vacuum in one dimension, where the initial vacuum is allowed. We get the upper and lower bounds of gas and liquid masses n and m by the continuity methods which we use to study the compressible Navier-Stokes equations.展开更多
In this paper,the Cauchy problem for a two-phase model with a magnetic field in three dimensions is considered.Based on a new linearized system with respect to(c−c_(∞),P−P_(∞),u,H)for constants c_(∞)≥0 and P_(∞)&...In this paper,the Cauchy problem for a two-phase model with a magnetic field in three dimensions is considered.Based on a new linearized system with respect to(c−c_(∞),P−P_(∞),u,H)for constants c_(∞)≥0 and P_(∞)>0,the existence theory of global strong solution is established when the initial data is close to its equilibrium in three dimensions for the small H^(2) initial data.We improve the existence results obtained by Wen and Zhu in[40]where an additional assumption that the initial perturbations are bounded in L^(1)-norm was needed.The energy method combined with the low-frequency and high-frequency decomposition is used to derive the decay of the solution and hence the global existence.As a by-product,the time decay estimates of the solution and its derivatives in the L^(2)-norm are obtained.展开更多
A two-phase model for the prediction of macrosegregation formed during solidification is presented. This model incorporates the descriptions of heat transfer, melt convection, solute transport, and solid movement on t...A two-phase model for the prediction of macrosegregation formed during solidification is presented. This model incorporates the descriptions of heat transfer, melt convection, solute transport, and solid movement on the system scale with microscopic relations for grain nucleation and growth. Then the model is used to simulate the solidification of a benchmark industrial 3.3-t steel ingot. Simulations are per- formed to investigate the effects of grain motion and pipe shrinkage formation on the final macrosegregation pattern. The model predictions are compared with experimental data and numerical results from literatures. It is demonstrated that the model is able to express the overall macrosegregation patterns in the ingot. Furthermore, the results show that it is essential to consider the motion of equiaxed grains and the formation of pipe shrinkage in modelling. Several issues for future model improvements are identified.展开更多
In this paper, laminar forced convection of CuO nanofluid is numerically investigated in sudden expansion microchannel with isotherm walls and different expansion ratios (ER). An Eulerian two-fluid model is considered...In this paper, laminar forced convection of CuO nanofluid is numerically investigated in sudden expansion microchannel with isotherm walls and different expansion ratios (ER). An Eulerian two-fluid model is considered to simulate the nanofluid flow inside the microchannel and the governing mass, momentum and energy equations for both phases are solved using the finite volume method. Eulerian-Eulerian two-phase model is very efficient because of considering the relative velocity and temperature of the phases and the nanoparticle concentration distribution. In solving the flow equations for both phases, the SIMPLE algorithm is modified for the coupling of the velocity and pressure and the continuity equations for both phases are combined in order to create the pressure correction equations. However, the Eulerian-Eulerian modeling results show higher heat transfer enhancement in comparison to pure water, so that for a 2% copper-water nanofluid, it has been observed a 35% increase of the heat transfer. The heat transfer enhancement increases with increase in Reynolds number and nanoparticle volume concentration, while the pressure drop increases only slightly. An investigation of the expansion ratio of microchannel shows that the average Nusselt number increases with decrease in expansion ratio as well as with increase in Reynolds number. Also, the Bifurcation has been occurred in higher Reynolds number that is different for each expansion ratio of the microchannel.展开更多
A depth-averaged quasi single-phase mixture model is proposed for debris flows over inclined bed slopes based on the shallow water hydrosediment-morphodynamic theory with multi grain sizes. The stresses due to fluctua...A depth-averaged quasi single-phase mixture model is proposed for debris flows over inclined bed slopes based on the shallow water hydrosediment-morphodynamic theory with multi grain sizes. The stresses due to fluctuations are incorporated based on analogy to turbulent flows, as estimated using the depth-averaged k-? turbulence model and a modification component. A fully conservative numerical algorithm, using wellbalanced slope limited centred scheme, is deployed to solve the governing equations. The present quasi single-phase model using four closure relationships for the bed shear stresses is evaluated against USGS experimental debris flow and compared with traditional quasi single-phase models and a recent physically enhanced two-phase model. It is found that the present quasi single-phase model performs much better than the traditional models, and is attractive in terms of computational cost while the two-phase model performs even better appreciably.展开更多
Underwater gas-liquid two-phase propulsion technology is an emerging propulsion method that offers high efficiency and unrestricted navigation speed.The integration of this technology into water ramjet engines can sig...Underwater gas-liquid two-phase propulsion technology is an emerging propulsion method that offers high efficiency and unrestricted navigation speed.The integration of this technology into water ramjet engines can significantly enhance propulsion efficiency and holds substantial potential for broad applications.However,forming a gas-liquid two-phase flow within the nozzle requires introducing a large amount of rammed seawater.At this time,there is a complex phase transition problem of combustion products in the combustion chamber,which makes the thermodynamic calculation for gas-liquid two-phase water ramjet engines particularly challenging.This paper proposes a thermodynamic calculation method for gas-liquid two-phase water ramjet engines,based on the energy equation for gas-liquid two-phase flow and traditional thermodynamic principles,enabling thermodynamic calculations under conditions of ultra-high water-fuel ratios.Additionally,ground ignition tests of the gas-liquid two-phase engine were conducted,yielding critical engine test parameters.The results demonstrate that the gas-liquid two-phase water ramjet engine achieves a high specific impulse,with a theoretical maximum specific impulse of up to 7000(N s)/kg.The multiphase flow effects significantly impact engine performance,with specific impulse losses reaching up to 25.86%.The error between the thrust and specific impulse in the ground test and the theoretical values is within 10%,validating the proposed thermodynamic calculation method as a reliable reference for further research on gas-liquid two-phase water ramjet engines.展开更多
In permafrost regions of the QinghaiXizang Plateau,embankments of the Qinghai-Xizang Highway and Qinghai-Xizang Railway experiencing roadside water accumulation exhibit more pronounced engineering deteriorations.A wid...In permafrost regions of the QinghaiXizang Plateau,embankments of the Qinghai-Xizang Highway and Qinghai-Xizang Railway experiencing roadside water accumulation exhibit more pronounced engineering deteriorations.A widely accepted view is that the accumulated water adjacent to the embankment possesses substantial thermal energy,which accelerates the degradation-even disappearance-of the underlying permafrost.Moreover,the presence of roadside water keeps the embankment soil in a persistently high-moisture state,thereby making the frozen-soil embankment more susceptible to deformation under traffic loading.However,in the permafrost regions of the QinghaiXizang Plateau,deteriorations of embankments affected by roadside water are more commonly manifested as undulating pavement surfaces,and extensive crack networks appear on the embankment crest even where thermosyphons are installed.These manifestations are not fully consistent with the deterioration mechanisms proposed by existing viewpoints.We propose the hypothesis that temperature gradients,formed due to the freezing and thawing processes between the roadside wateraffected soil and the roadbed soil,lead to moisture migration under the influence of temperature gradients,resulting in frost heave and thaw settlement in the roadbed soil.To validate this hypothesis,we conducted the following investigations sequentially.Initially,we selected a roadbed with a thermosyphon(TPCT)system,which has a significant cooling effect,as the study object.By analyzing the temperature monitoring data of the roadbed section,the temperature variance was calculated to identify the time nodes where the temperature gradient of the roadbed soil was maximum and minimum.Subsequently,corresponding roadbed temperature distribution maps were drawn,illustrating the changes in the temperature and position of the lowtemperature core near the TPCT over time.Furthermore,using small-scale indoor model experiments,we qualitatively concluded that moisture in the soil migrates toward the TPCT due to the temperature gradient.Thereafter,combining borehole water content data and precipitation data from the sloped terrain construction site,the formation mechanisms and timing characteristics of roadside water accumulation were analyzed.Ultimately,by integrating the ground temperature data,air temperature data,roadside water formation mechanisms,and the operating characteristics of the TPCT,it was concluded that roadside water,while in a thawed state during TPCT operation,acts as a supplementary source for moisture migration in the roadbed soil.This migration leads to cracking in the TPCT roadbed.Therefore,this study reveals a novel damage mechanism:asynchronous freeze-thaw processes induce temperature gradients,which drive the migration of roadside water into the roadbed and are responsible for the cracking damage.展开更多
This study investigates the droplet formation for the liquid–liquid two-phase flow within a square T-junction microchannel through numerical simulation using volume of fluid method and experimental visualization usin...This study investigates the droplet formation for the liquid–liquid two-phase flow within a square T-junction microchannel through numerical simulation using volume of fluid method and experimental visualization using high-speed camera imaging.The T-junction microchannel has a cross-sectional width of 0.6 mm and a total length of 27.3 mm.The solution of cyclohexane with 2%and 3%mass concentrations of sorbitan trioleate surfactant were used as the continuous phase,and water was used as the dispersed phase.Slug flow,characteristic of squeezing regime,were predominantly observed.The effects of liquid–liquid two-phase flow rate ratio,and dimensionless number on droplet size,and pressure drop were investigated.The squeezing regime was mapped for 0.0005≤Ca_(c)≤0.0052(capillary number)and 0.1≤q≤10(flow rate ratio).The pressure drops of slugs were in the range from 40 Pa to 200 Pa.The slug lengths were measured between 1 mm and 9 mm.A universal flow map dependent on Ca_(c)Re_(d)^(0.5) are projected to investigate the droplet formation behavior in T-junction microchannel.Correlation expressions are proposed to predict pressure drops and the slug lengths for liquid–liquid two-phase flow in a square T-junction microchannel,using dimensionless numbers such as flow rate ratio and capillary number.The result shows that large continuous phase flow rates facilitate smaller slugs,whereas higher dispersed phase flow rates result in longer shorts.展开更多
Gas-liquid two-phase flow in fractal porous media is pivotal for engineering applications,yet it remains challenging to be accurately characterized due to complex microstructure-flow interactions.This study establishe...Gas-liquid two-phase flow in fractal porous media is pivotal for engineering applications,yet it remains challenging to be accurately characterized due to complex microstructure-flow interactions.This study establishes a pore-scale numerical framework integratingMonte Carlo-generated fractal porousmedia with Volume of Fluid(VOF)simulations to unravel the coupling among pore distribution characterized by fractal dimension(Df),flow dynamics,and displacement efficiency.A pore-scale model based on the computed tomography(CT)microstructure of Berea sandstone is established,and the simulation results are compared with experimental data.Good agreement is found in phase distribution,breakthrough behavior,and flow path morphology,confirming the reliability of the numerical simulation method.Ten fractal porous media models with Df ranging from 1.25~1.7 were constructed using a Monte-Carlo approach.The gas-liquid two-phase flow dynamics was characterized using the VOF solver across gas injection rates of 0.05-5m/s,inwhich the time-resolved two-phase distribution patternswere systematically recorded.The results reveal that smaller fractal dimensions(Df=1.25~1.45)accelerate fingering breakthrough(peak velocity is 1.73 m/s at Df=1.45)due to a bimodal pore size distribution dominated by narrow channels.Increasing Df amplifies vorticity generation by about 3 times(eddy viscosity is 0.033 Pa⋅s at Df=1.7)through reduced interfacial curvature,while tortuosity-driven pressure differentials transition from sharp increases(0.4~6.3 Pa at Df=1.25~1.3)to inertial plateaus(4.8 Pa at Df=1.7).A nonlinear increase in equilibrium gas volume fraction(fav=0.692 at Df=1.7)emerges from residual gas saturation and turbulence-enhanced dispersion.This behavior is further modulated by flow velocity,with fav peaking at 0.72 under capillary-dominated conditions(0.05 m/s),but decreasing to 0.65 in the inertial regime(0.5 m/s).The work quantitatively links fractal topology to multiphase flow regimes,demonstrating the critical role of Df in governing preferential pathways,energy dissipation,and phase distribution.展开更多
Polymer flooding is an important means of improving oil recovery and is widely used in Daqing,Xinjiang,and Shengli oilfields,China.Different from conventional injection media such as water and gas,viscoelastic polymer...Polymer flooding is an important means of improving oil recovery and is widely used in Daqing,Xinjiang,and Shengli oilfields,China.Different from conventional injection media such as water and gas,viscoelastic polymer solutions exhibit non-Newtonian and nonlinear flow behavior including shear thinning and shear thickening,polymer convection,diffusion,adsorption,retention,inaccessible pore volume,and reduced effective permeability.However,available well test model of polymer flooding wells generally simplifies these characteristics on pressure transient response,which may lead to inaccurate results.This work proposes a novel two-phase numerical well test model to better describe the polymer viscoelasticity and nonlinear flow behavior.Different influence factors that related to near-well blockage during polymer flooding process,including the degree of blockage(inner zone permeability),the extent of blockage(composite radius),and polymer flooding front radius are explored to investigate these impacts on bottom hole pressure responses.Results show that polymer viscoelasticity has a significant impact on the transitional flow segment of type curves,and the effects of near-well formation blockage and polymer concentration distribution on well test curves are very similar.Thus,to accurately interpret the degree of near-well blockage in injection wells,it is essential to first eliminate the influence of polymer viscoelasticity.Finally,a field case is comprehensively analyzed and discussed to illustrate the applicability of the proposed model.展开更多
In multiphase pumps transporting gas-liquid two-phase flows,the high-speed rotation of the impeller induces complex deformations in bubble shapes within the flow domain,making the prediction of gasliquid two-phase dra...In multiphase pumps transporting gas-liquid two-phase flows,the high-speed rotation of the impeller induces complex deformations in bubble shapes within the flow domain,making the prediction of gasliquid two-phase drag forces highly challenging in numerical simulations.To achieve precise prediction of the drag forces on irregular bubbles within multiphase pumps,this study modifies the existing bubble drag force model and applies the revised model to the prediction of gas-liquid two-phase flow within multiphase pumps.The research findings indicate that the modified drag force model significantly enhances the accuracy of predicting flow characteristics within the pump,particularly under high gas volume fraction conditions.The simulation results for gas phase distribution and vorticity exhibit strong agreement with experimental data.The modified drag model better captures the accumulation of the gas phase at the suction side of the impeller outlet.It also accurately predicts the vortex characteristics induced by bubble backflow from the trailing edges of the diffuser.Additionally,the adjustment of the drag coefficient enhances the model’s ability to represent local flow field characteristics,thereby optimizing the performance simulation methods of multiphase pumps.Compared to traditional drag force models,the modified model reduces prediction errors in head and efficiency by 36.4%and 27.5%,respectively.These results provide important theoretical foundations and model support for improving the accuracy of gas-liquid two-phase flow simulations and optimizing the design of multiphase pumps under high gas volume fraction conditions.展开更多
Two-phase partitioning bioreactors(TPPBs)have been widely used because they overcome the mass-transfer limitation of hydrophobic volatile organic compounds(VOCs)in waste gas biological treatments.Understanding the mec...Two-phase partitioning bioreactors(TPPBs)have been widely used because they overcome the mass-transfer limitation of hydrophobic volatile organic compounds(VOCs)in waste gas biological treatments.Understanding the mechanisms of mass-transfer enhancement in TPPBs would enable efficient predictions for further industrial applications.In this study,influences of gradually increasing silicone oil ratio on the TPPB was explored,and a 94.35%reduction of the n-hexane partition coefficient was observed with 0.1 vol.%silicone,which increased to 80.7%along with a 40-fold removal efficiency enhancement in the stabilised removal period.The elimination capacity increased from 1.47 to 148.35 g/(m^(3)·h),i.e.a 101-fold increase compared with that of the single-phase reactors,when 10 vol.%(3 Critical Micelle Concentration)silicone oil was added.The significantly promoted partition coefficient was the main reason for the mass transfer enhancement,which covered the negative influences of the decreased total mass-transfer coefficient with increasing silicone oil volume ratio.The gradually rising stirring rate was benefit to the n-hexane removal,which became negative when the dominant resistance shifted from mass transfer to biodegradation.Moreover,a mass-transfer-reaction kinetic model of the TPPB was constructed based on the balance of n-hexane concentration,dissolved oxygen and biomass.Similar to the mechanism,the partition factor was predicted sensitive to the removal performance,and another five sensitive parameters were found simultaneously.This forecasting method enables the optimisation of TPPB performance and provides theoretical support for hydrophobic VOCs degradation.展开更多
By combining with an improved model on engraving process,a two-phase flow interior ballistic model has been proposed to accurately predict the flow and energy conversion behaviors of pyrotechnic actuators.Using comput...By combining with an improved model on engraving process,a two-phase flow interior ballistic model has been proposed to accurately predict the flow and energy conversion behaviors of pyrotechnic actuators.Using computational fluid dynamics(CFD),the two-phase flow and piston engraving characteristics of a pyrotechnic actuator are investigated.Initially,the current model was utilized to examine the intricate,multi-dimensional flow,and energy conversion characteristics of the propellant grains and combustion gas within the pyrotechnic actuator chamber.It was discovered that the combustion gas on the wall's constant transition from potential to kinetic energy,along with the combined effect of the propellant motion,are what create the pressure oscillation within the chamber.Additionally,a numerical analysis was conducted to determine the impact of various parameters on the pressure oscillation and piston motion,including pyrotechnic charge,pyrotechnic particle size,and chamber structural dimension.The findings show that decreasing the pyrotechnic charge will lower the terminal velocity,while increasing and decreasing the pyrotechnic particle size will reduce the pressure oscillation in the chamber.The pyrotechnic particle size has minimal bearing on the terminal velocity.The results of this investigation offer a trustworthy forecasting instrument for comprehending and creating pyrotechnic actuator designs.展开更多
As space technology advances,thermal control systems must effectively collect and dissipate heat from distributed,multi-source environments.Loop heat pipe is a highly reliable two-phase heat transfer component,but it ...As space technology advances,thermal control systems must effectively collect and dissipate heat from distributed,multi-source environments.Loop heat pipe is a highly reliable two-phase heat transfer component,but it has several limitations when addressing multi-source heat dissipation.Inspired by the transport and heat dissipation system of plants,large trees achieve stable and efficient liquid supply under the influence of two driving forces:capillary force during transpiration in the leaves(pull)and root pressure generated by osmotic pressure in the roots(push).The root pressure provides an effective liquid supply with a driving force exceeding 2 MPa,far greater than the driving force in conventional capillary-pumped two-phase loops.Research has shown that osmotic heat pipes offer a powerful driving force,and combining osmotic pressure with capillary force has significant advantages.Therefore,this paper designs a multi-evaporator,dual-drive two-phase loop,using both osmotic pressure and capillary force to solve the multi-source heat dissipation challenge.First,a transmembrane water flux model for the osmotic pressure-driven device was established to predict the maximum heat transfer capacity of the dual-drive two-phase loop.Then,an experimental setup for a multi-evaporator“osmotic pressure+capillary force”dual-drive two-phase loop was constructed,capable of transferring at least 235 W of power under a reverse gravity condition of 20 m.The study also analyzed the effects of reverse gravity height,heat load distribution among the three evaporators,startup sequence,and varying branch resistances on the performance of the dual-drive two-phase loop.展开更多
The challenge of wide brine source and its additional problems come from the economy(energy consumption and other costs),security(re-dissolution of surrounding salt rocks),and environment(groundwater pollution by brin...The challenge of wide brine source and its additional problems come from the economy(energy consumption and other costs),security(re-dissolution of surrounding salt rocks),and environment(groundwater pollution by brine)of salt cavern oil storage are worth examining to improve the efficiency of oil storage.Against this background,this work presented an operating mode of salt cavern oil and gas co-storage and using natural gas displacement for petroleum recovery.A gas-oil two-phase flow model with gas dissolution and exsolution was proposed to evaluate the application prospects of the new method precisely.Numerical studies indicated that the gas void fraction at the wellhead under quasi-steady state conditions is approximately 0.153,which belongs to bubbly flow,and the pressure at the wellhead of the central tube increased from 5.54 to 6.12 MPa during the entire transient flow stage,with an increase of 10.47%.Compared to the traditional method of using brine as the working fluid,the pump pressure rises from 2.92 to 14.01 MPa.However,if the new mode can be linked with the salt cavern gas storage and when the initial wellhead gas pressure exceeds 13 MPa,the energy consumption of the new method will be lower than that of the traditional brine-based operational mode.A new empirical formula is proposed to determine the two-phase flow pattern under different operating parameters.A special focus was given to energy consumption for oil recovery,which grows roughly in accordance with the operating pressure and oil recovery rate.However,the energy cost per volume of crude oil remains almost unchanged.This work provided a new solution for the serious brine problem and is expected to achieve petroleum recovery through natural gas displacement.展开更多
Current studies on carbon nanotube (CNT) size effects predominantly employ Eringen’s differential nonlocal model, which is widely recognized as ill-suited for bounded domains. This paper investigates the free vibrati...Current studies on carbon nanotube (CNT) size effects predominantly employ Eringen’s differential nonlocal model, which is widely recognized as ill-suited for bounded domains. This paper investigates the free vibration of multi-walled CNTs (MWCNTs) with mathematically well-posed two-phase strain-driven and stress-driven nonlocal integral models incorporating the bi-Helmholtz kernel. The van der Waals (vdW) forces coupling MWCNT layers are similarly modeled as size-dependent via the bi-Helmholtz two-phase nonlocal integral framework. Critically, conventional pure strain-driven or stress-driven formulations become over-constrained when nonlocal vdW interactions are considered. The two-phase strategy resolves this limitation by enabling consistent coupling. Each bi-Helmholtz integral constitutive equation is equivalently transformed into a differential form requiring four additional constitutive boundary conditions (CBCs). The numerical solutions are obtained with the generalized differential quadrature method (GDQM) for these coupled higher-order equations. The parametric studies on double-walled CNTs (DWCNTs) and triple-walled CNTs (TWCNTs) elucidate the nonlocal effects predicted by both formulations. Additionally, the influence of nonlocal parameters within vdW forces is systematically evaluated to comprehensively characterize the size effects in MWCNTs.展开更多
The volume fraction of the solid and liquid phase of debris flows,which evolves simultaneously across terrains,largely determines the dynamic property of debris flows.The entrainment process significantly influences t...The volume fraction of the solid and liquid phase of debris flows,which evolves simultaneously across terrains,largely determines the dynamic property of debris flows.The entrainment process significantly influences the amplitude of the volume fraction.In this paper,we present a depth-averaged two-phase debris-flow model describing the simultaneous evolution of the phase velocity and depth,the solid and fluid volume fractions and the bed morphological evolution.The model employs the Mohr–Coulomb plasticity for the solid stress,and the fluid stress is modeled as a Newtonian viscous stress.The interfacial momentum transfer includes viscous drag and buoyancy.A new extended entrainment rate formula that satisfies the boundary momentum jump condition(Iverson and Ouyang,2015)is presented.In this formula,the basal traction stress is a function of the solid volume fraction and can take advantage of both the Coulomb and velocity-dependent friction models.A finite volume method using Roe’s Riemann approximation is suggested to solve the equations.Three computational cases are conducted and compared with experiments or previous results.The results show that the current computational model and framework are robust and suitable for capturing the characteristics of debris flows.展开更多
Biot-flow and squirt-flow are the two most important fluid flow mechanisms in porous media containing fluids. Based on the BISQ （Biot-Squirt） model where the two mechanisms are treated simultaneously, the elastic wa...Biot-flow and squirt-flow are the two most important fluid flow mechanisms in porous media containing fluids. Based on the BISQ （Biot-Squirt） model where the two mechanisms are treated simultaneously, the elastic wave-field simulation in the porous medium is limited to two-dimensions and two-components （2D2C） or two-dimensions and three-components （2D3C）. There is no previous report on wave simulation in three- dimensions and three-components. Only through three dimensional numerical simulations can we have an overall understanding of wave field coupling relations and the spatial distribution characteristics between the solid and fluid phases in the dual-phase anisotropic medium. In this paper, based on the BISQ equation, we present elastic wave propagation in a three dimensional dual-phase anisotropic medium simulated by the staggered-grid high-order finite-difference method. We analyze the resulting wave fields and show that the results are an improvement.展开更多
To improve the accuracy of the conventional finite-difference method, finitedifference numerical modeling methods of any even-order accuracy are recommended. We introduce any even-order accuracy difference schemes of ...To improve the accuracy of the conventional finite-difference method, finitedifference numerical modeling methods of any even-order accuracy are recommended. We introduce any even-order accuracy difference schemes of any-order derivatives derived from Taylor series expansion. Then, a finite-difference numerical modeling method with any evenorder accuracy is utilized to simulate seismic wave propagation in two-phase anisotropic media. Results indicate that modeling accuracy improves with the increase of difference accuracy order number. It is essential to find the optimal order number, grid size, and time step to balance modeling precision and computational complexity. Four kinds of waves, static mode in the source point, SV wave cusps, reflection and transmission waves are observed in two-phase anisotropic media through modeling.展开更多
文摘The main purpose of this study is to survey numerically comparison of two- phase and single phase of heat transfer and flow field of copper-water nanofluid in a wavy channel. The computational fluid dynamics （CFD） prediction is used for heat transfer and flow prediction of the single phase and three different two-phase models （mixture, volume of fluid （VOF）, and Eulerian）. The heat transfer coefficient, temperature, and velocity distributions are investigated. The results show that the differences between the temperature fie].d in the single phase and two-phase models are greater than those in the hydrodynamic tleld. Also, it is found that the heat transfer coefficient predicted by the single phase model is enhanced by increasing the volume fraction of nanoparticles for all Reynolds numbers; while for the two-phase models, when the Reynolds number is low, increasing the volume fraction of nanoparticles will enhance the heat transfer coefficient in the front and the middle of the wavy channel, but gradually decrease along the wavy channel.
基金Supported by the National Natural Science Foundation of China(11171340)
文摘In this work, we obtain the global existence and uniqueness of classical solu-tions to a viscous liquid-gas two-phase model with mass-dependent viscosity and vacuum in one dimension, where the initial vacuum is allowed. We get the upper and lower bounds of gas and liquid masses n and m by the continuity methods which we use to study the compressible Navier-Stokes equations.
基金supported by the National Natural Science Foundation of China(11871341 and 12071152).
文摘In this paper,the Cauchy problem for a two-phase model with a magnetic field in three dimensions is considered.Based on a new linearized system with respect to(c−c_(∞),P−P_(∞),u,H)for constants c_(∞)≥0 and P_(∞)>0,the existence theory of global strong solution is established when the initial data is close to its equilibrium in three dimensions for the small H^(2) initial data.We improve the existence results obtained by Wen and Zhu in[40]where an additional assumption that the initial perturbations are bounded in L^(1)-norm was needed.The energy method combined with the low-frequency and high-frequency decomposition is used to derive the decay of the solution and hence the global existence.As a by-product,the time decay estimates of the solution and its derivatives in the L^(2)-norm are obtained.
基金supported by the National Science and Technology Major Project of China (No.2011ZX04014-052)the National Basic Research Priorities Program of China (No.2011CB012900)
文摘A two-phase model for the prediction of macrosegregation formed during solidification is presented. This model incorporates the descriptions of heat transfer, melt convection, solute transport, and solid movement on the system scale with microscopic relations for grain nucleation and growth. Then the model is used to simulate the solidification of a benchmark industrial 3.3-t steel ingot. Simulations are per- formed to investigate the effects of grain motion and pipe shrinkage formation on the final macrosegregation pattern. The model predictions are compared with experimental data and numerical results from literatures. It is demonstrated that the model is able to express the overall macrosegregation patterns in the ingot. Furthermore, the results show that it is essential to consider the motion of equiaxed grains and the formation of pipe shrinkage in modelling. Several issues for future model improvements are identified.
文摘In this paper, laminar forced convection of CuO nanofluid is numerically investigated in sudden expansion microchannel with isotherm walls and different expansion ratios (ER). An Eulerian two-fluid model is considered to simulate the nanofluid flow inside the microchannel and the governing mass, momentum and energy equations for both phases are solved using the finite volume method. Eulerian-Eulerian two-phase model is very efficient because of considering the relative velocity and temperature of the phases and the nanoparticle concentration distribution. In solving the flow equations for both phases, the SIMPLE algorithm is modified for the coupling of the velocity and pressure and the continuity equations for both phases are combined in order to create the pressure correction equations. However, the Eulerian-Eulerian modeling results show higher heat transfer enhancement in comparison to pure water, so that for a 2% copper-water nanofluid, it has been observed a 35% increase of the heat transfer. The heat transfer enhancement increases with increase in Reynolds number and nanoparticle volume concentration, while the pressure drop increases only slightly. An investigation of the expansion ratio of microchannel shows that the average Nusselt number increases with decrease in expansion ratio as well as with increase in Reynolds number. Also, the Bifurcation has been occurred in higher Reynolds number that is different for each expansion ratio of the microchannel.
基金funded by Natural Science Foundation of China(Grants Nos.51279144 and 11432015)
文摘A depth-averaged quasi single-phase mixture model is proposed for debris flows over inclined bed slopes based on the shallow water hydrosediment-morphodynamic theory with multi grain sizes. The stresses due to fluctuations are incorporated based on analogy to turbulent flows, as estimated using the depth-averaged k-? turbulence model and a modification component. A fully conservative numerical algorithm, using wellbalanced slope limited centred scheme, is deployed to solve the governing equations. The present quasi single-phase model using four closure relationships for the bed shear stresses is evaluated against USGS experimental debris flow and compared with traditional quasi single-phase models and a recent physically enhanced two-phase model. It is found that the present quasi single-phase model performs much better than the traditional models, and is attractive in terms of computational cost while the two-phase model performs even better appreciably.
基金supported by the Stable Support Fund forBasic Disciplines,China(No.3072024WD0201)。
文摘Underwater gas-liquid two-phase propulsion technology is an emerging propulsion method that offers high efficiency and unrestricted navigation speed.The integration of this technology into water ramjet engines can significantly enhance propulsion efficiency and holds substantial potential for broad applications.However,forming a gas-liquid two-phase flow within the nozzle requires introducing a large amount of rammed seawater.At this time,there is a complex phase transition problem of combustion products in the combustion chamber,which makes the thermodynamic calculation for gas-liquid two-phase water ramjet engines particularly challenging.This paper proposes a thermodynamic calculation method for gas-liquid two-phase water ramjet engines,based on the energy equation for gas-liquid two-phase flow and traditional thermodynamic principles,enabling thermodynamic calculations under conditions of ultra-high water-fuel ratios.Additionally,ground ignition tests of the gas-liquid two-phase engine were conducted,yielding critical engine test parameters.The results demonstrate that the gas-liquid two-phase water ramjet engine achieves a high specific impulse,with a theoretical maximum specific impulse of up to 7000(N s)/kg.The multiphase flow effects significantly impact engine performance,with specific impulse losses reaching up to 25.86%.The error between the thrust and specific impulse in the ground test and the theoretical values is within 10%,validating the proposed thermodynamic calculation method as a reliable reference for further research on gas-liquid two-phase water ramjet engines.
基金supported by the Major Science and Technology Project of Gansu Province(Grant No.24ZD13FA003 and 23ZDWA005)National Natural Science Foundation of China(Grant No.42371140,42301163,41971087 and 42272332)the program of the State Key Laboratory of Cryospheric Science and Frozen Soil Engineering,CAS(No.CSFSEZZ-2411)。
文摘In permafrost regions of the QinghaiXizang Plateau,embankments of the Qinghai-Xizang Highway and Qinghai-Xizang Railway experiencing roadside water accumulation exhibit more pronounced engineering deteriorations.A widely accepted view is that the accumulated water adjacent to the embankment possesses substantial thermal energy,which accelerates the degradation-even disappearance-of the underlying permafrost.Moreover,the presence of roadside water keeps the embankment soil in a persistently high-moisture state,thereby making the frozen-soil embankment more susceptible to deformation under traffic loading.However,in the permafrost regions of the QinghaiXizang Plateau,deteriorations of embankments affected by roadside water are more commonly manifested as undulating pavement surfaces,and extensive crack networks appear on the embankment crest even where thermosyphons are installed.These manifestations are not fully consistent with the deterioration mechanisms proposed by existing viewpoints.We propose the hypothesis that temperature gradients,formed due to the freezing and thawing processes between the roadside wateraffected soil and the roadbed soil,lead to moisture migration under the influence of temperature gradients,resulting in frost heave and thaw settlement in the roadbed soil.To validate this hypothesis,we conducted the following investigations sequentially.Initially,we selected a roadbed with a thermosyphon(TPCT)system,which has a significant cooling effect,as the study object.By analyzing the temperature monitoring data of the roadbed section,the temperature variance was calculated to identify the time nodes where the temperature gradient of the roadbed soil was maximum and minimum.Subsequently,corresponding roadbed temperature distribution maps were drawn,illustrating the changes in the temperature and position of the lowtemperature core near the TPCT over time.Furthermore,using small-scale indoor model experiments,we qualitatively concluded that moisture in the soil migrates toward the TPCT due to the temperature gradient.Thereafter,combining borehole water content data and precipitation data from the sloped terrain construction site,the formation mechanisms and timing characteristics of roadside water accumulation were analyzed.Ultimately,by integrating the ground temperature data,air temperature data,roadside water formation mechanisms,and the operating characteristics of the TPCT,it was concluded that roadside water,while in a thawed state during TPCT operation,acts as a supplementary source for moisture migration in the roadbed soil.This migration leads to cracking in the TPCT roadbed.Therefore,this study reveals a novel damage mechanism:asynchronous freeze-thaw processes induce temperature gradients,which drive the migration of roadside water into the roadbed and are responsible for the cracking damage.
基金supports for this project from the National Natural Science Foundation of China(22378295).
文摘This study investigates the droplet formation for the liquid–liquid two-phase flow within a square T-junction microchannel through numerical simulation using volume of fluid method and experimental visualization using high-speed camera imaging.The T-junction microchannel has a cross-sectional width of 0.6 mm and a total length of 27.3 mm.The solution of cyclohexane with 2%and 3%mass concentrations of sorbitan trioleate surfactant were used as the continuous phase,and water was used as the dispersed phase.Slug flow,characteristic of squeezing regime,were predominantly observed.The effects of liquid–liquid two-phase flow rate ratio,and dimensionless number on droplet size,and pressure drop were investigated.The squeezing regime was mapped for 0.0005≤Ca_(c)≤0.0052(capillary number)and 0.1≤q≤10(flow rate ratio).The pressure drops of slugs were in the range from 40 Pa to 200 Pa.The slug lengths were measured between 1 mm and 9 mm.A universal flow map dependent on Ca_(c)Re_(d)^(0.5) are projected to investigate the droplet formation behavior in T-junction microchannel.Correlation expressions are proposed to predict pressure drops and the slug lengths for liquid–liquid two-phase flow in a square T-junction microchannel,using dimensionless numbers such as flow rate ratio and capillary number.The result shows that large continuous phase flow rates facilitate smaller slugs,whereas higher dispersed phase flow rates result in longer shorts.
基金funded by the National Key R&D Program of China,China(Grant No.2023YFB4005500)National Natural Science Foundation of China,China(Grant Nos.52379113 and 52379114).
文摘Gas-liquid two-phase flow in fractal porous media is pivotal for engineering applications,yet it remains challenging to be accurately characterized due to complex microstructure-flow interactions.This study establishes a pore-scale numerical framework integratingMonte Carlo-generated fractal porousmedia with Volume of Fluid(VOF)simulations to unravel the coupling among pore distribution characterized by fractal dimension(Df),flow dynamics,and displacement efficiency.A pore-scale model based on the computed tomography(CT)microstructure of Berea sandstone is established,and the simulation results are compared with experimental data.Good agreement is found in phase distribution,breakthrough behavior,and flow path morphology,confirming the reliability of the numerical simulation method.Ten fractal porous media models with Df ranging from 1.25~1.7 were constructed using a Monte-Carlo approach.The gas-liquid two-phase flow dynamics was characterized using the VOF solver across gas injection rates of 0.05-5m/s,inwhich the time-resolved two-phase distribution patternswere systematically recorded.The results reveal that smaller fractal dimensions(Df=1.25~1.45)accelerate fingering breakthrough(peak velocity is 1.73 m/s at Df=1.45)due to a bimodal pore size distribution dominated by narrow channels.Increasing Df amplifies vorticity generation by about 3 times(eddy viscosity is 0.033 Pa⋅s at Df=1.7)through reduced interfacial curvature,while tortuosity-driven pressure differentials transition from sharp increases(0.4~6.3 Pa at Df=1.25~1.3)to inertial plateaus(4.8 Pa at Df=1.7).A nonlinear increase in equilibrium gas volume fraction(fav=0.692 at Df=1.7)emerges from residual gas saturation and turbulence-enhanced dispersion.This behavior is further modulated by flow velocity,with fav peaking at 0.72 under capillary-dominated conditions(0.05 m/s),but decreasing to 0.65 in the inertial regime(0.5 m/s).The work quantitatively links fractal topology to multiphase flow regimes,demonstrating the critical role of Df in governing preferential pathways,energy dissipation,and phase distribution.
基金supported by the National Natural Science Foundation of China(52104049)the Young Elite Scientist Sponsorship Program by Beijing Association for Science and Technology(BYESS2023262)。
文摘Polymer flooding is an important means of improving oil recovery and is widely used in Daqing,Xinjiang,and Shengli oilfields,China.Different from conventional injection media such as water and gas,viscoelastic polymer solutions exhibit non-Newtonian and nonlinear flow behavior including shear thinning and shear thickening,polymer convection,diffusion,adsorption,retention,inaccessible pore volume,and reduced effective permeability.However,available well test model of polymer flooding wells generally simplifies these characteristics on pressure transient response,which may lead to inaccurate results.This work proposes a novel two-phase numerical well test model to better describe the polymer viscoelasticity and nonlinear flow behavior.Different influence factors that related to near-well blockage during polymer flooding process,including the degree of blockage(inner zone permeability),the extent of blockage(composite radius),and polymer flooding front radius are explored to investigate these impacts on bottom hole pressure responses.Results show that polymer viscoelasticity has a significant impact on the transitional flow segment of type curves,and the effects of near-well formation blockage and polymer concentration distribution on well test curves are very similar.Thus,to accurately interpret the degree of near-well blockage in injection wells,it is essential to first eliminate the influence of polymer viscoelasticity.Finally,a field case is comprehensively analyzed and discussed to illustrate the applicability of the proposed model.
基金funded by Sichuan Natural Science Foundation Outstanding Youth Science Foundation(No.2024NSFJQ0012)Key project of Regional Innovation and Development Joint Fund of National Natural Science Foundation(No.U23A20669)Sichuan Science and Technology Program(2022ZDZX0041).
文摘In multiphase pumps transporting gas-liquid two-phase flows,the high-speed rotation of the impeller induces complex deformations in bubble shapes within the flow domain,making the prediction of gasliquid two-phase drag forces highly challenging in numerical simulations.To achieve precise prediction of the drag forces on irregular bubbles within multiphase pumps,this study modifies the existing bubble drag force model and applies the revised model to the prediction of gas-liquid two-phase flow within multiphase pumps.The research findings indicate that the modified drag force model significantly enhances the accuracy of predicting flow characteristics within the pump,particularly under high gas volume fraction conditions.The simulation results for gas phase distribution and vorticity exhibit strong agreement with experimental data.The modified drag model better captures the accumulation of the gas phase at the suction side of the impeller outlet.It also accurately predicts the vortex characteristics induced by bubble backflow from the trailing edges of the diffuser.Additionally,the adjustment of the drag coefficient enhances the model’s ability to represent local flow field characteristics,thereby optimizing the performance simulation methods of multiphase pumps.Compared to traditional drag force models,the modified model reduces prediction errors in head and efficiency by 36.4%and 27.5%,respectively.These results provide important theoretical foundations and model support for improving the accuracy of gas-liquid two-phase flow simulations and optimizing the design of multiphase pumps under high gas volume fraction conditions.
基金supported by the National Key Research and Development Program of China(No.2022YFC3702000)the National Natural Science Foundation of China(No.52070169)the Project of Bureau of Science and Technology of Zhoushan,China(No.2022C41013).
文摘Two-phase partitioning bioreactors(TPPBs)have been widely used because they overcome the mass-transfer limitation of hydrophobic volatile organic compounds(VOCs)in waste gas biological treatments.Understanding the mechanisms of mass-transfer enhancement in TPPBs would enable efficient predictions for further industrial applications.In this study,influences of gradually increasing silicone oil ratio on the TPPB was explored,and a 94.35%reduction of the n-hexane partition coefficient was observed with 0.1 vol.%silicone,which increased to 80.7%along with a 40-fold removal efficiency enhancement in the stabilised removal period.The elimination capacity increased from 1.47 to 148.35 g/(m^(3)·h),i.e.a 101-fold increase compared with that of the single-phase reactors,when 10 vol.%(3 Critical Micelle Concentration)silicone oil was added.The significantly promoted partition coefficient was the main reason for the mass transfer enhancement,which covered the negative influences of the decreased total mass-transfer coefficient with increasing silicone oil volume ratio.The gradually rising stirring rate was benefit to the n-hexane removal,which became negative when the dominant resistance shifted from mass transfer to biodegradation.Moreover,a mass-transfer-reaction kinetic model of the TPPB was constructed based on the balance of n-hexane concentration,dissolved oxygen and biomass.Similar to the mechanism,the partition factor was predicted sensitive to the removal performance,and another five sensitive parameters were found simultaneously.This forecasting method enables the optimisation of TPPB performance and provides theoretical support for hydrophobic VOCs degradation.
基金supported by the National Natural Science Foundation of China(Grant No.11972194).
文摘By combining with an improved model on engraving process,a two-phase flow interior ballistic model has been proposed to accurately predict the flow and energy conversion behaviors of pyrotechnic actuators.Using computational fluid dynamics(CFD),the two-phase flow and piston engraving characteristics of a pyrotechnic actuator are investigated.Initially,the current model was utilized to examine the intricate,multi-dimensional flow,and energy conversion characteristics of the propellant grains and combustion gas within the pyrotechnic actuator chamber.It was discovered that the combustion gas on the wall's constant transition from potential to kinetic energy,along with the combined effect of the propellant motion,are what create the pressure oscillation within the chamber.Additionally,a numerical analysis was conducted to determine the impact of various parameters on the pressure oscillation and piston motion,including pyrotechnic charge,pyrotechnic particle size,and chamber structural dimension.The findings show that decreasing the pyrotechnic charge will lower the terminal velocity,while increasing and decreasing the pyrotechnic particle size will reduce the pressure oscillation in the chamber.The pyrotechnic particle size has minimal bearing on the terminal velocity.The results of this investigation offer a trustworthy forecasting instrument for comprehending and creating pyrotechnic actuator designs.
基金Science Foundation for Distinguished Young Scholars 2020-JCJQ-ZQ-042 Intelligent and Bionic Spacecraft Thermal Control Technology Inspired by Tree Sap Transport Principle.
文摘As space technology advances,thermal control systems must effectively collect and dissipate heat from distributed,multi-source environments.Loop heat pipe is a highly reliable two-phase heat transfer component,but it has several limitations when addressing multi-source heat dissipation.Inspired by the transport and heat dissipation system of plants,large trees achieve stable and efficient liquid supply under the influence of two driving forces:capillary force during transpiration in the leaves(pull)and root pressure generated by osmotic pressure in the roots(push).The root pressure provides an effective liquid supply with a driving force exceeding 2 MPa,far greater than the driving force in conventional capillary-pumped two-phase loops.Research has shown that osmotic heat pipes offer a powerful driving force,and combining osmotic pressure with capillary force has significant advantages.Therefore,this paper designs a multi-evaporator,dual-drive two-phase loop,using both osmotic pressure and capillary force to solve the multi-source heat dissipation challenge.First,a transmembrane water flux model for the osmotic pressure-driven device was established to predict the maximum heat transfer capacity of the dual-drive two-phase loop.Then,an experimental setup for a multi-evaporator“osmotic pressure+capillary force”dual-drive two-phase loop was constructed,capable of transferring at least 235 W of power under a reverse gravity condition of 20 m.The study also analyzed the effects of reverse gravity height,heat load distribution among the three evaporators,startup sequence,and varying branch resistances on the performance of the dual-drive two-phase loop.
基金The financial support from the National Science and Technology Major Project,China(No.2024ZD1004107)the Natural Science Foundation of Wuhan(No.2024040701010062)is greatly appreciated。
文摘The challenge of wide brine source and its additional problems come from the economy(energy consumption and other costs),security(re-dissolution of surrounding salt rocks),and environment(groundwater pollution by brine)of salt cavern oil storage are worth examining to improve the efficiency of oil storage.Against this background,this work presented an operating mode of salt cavern oil and gas co-storage and using natural gas displacement for petroleum recovery.A gas-oil two-phase flow model with gas dissolution and exsolution was proposed to evaluate the application prospects of the new method precisely.Numerical studies indicated that the gas void fraction at the wellhead under quasi-steady state conditions is approximately 0.153,which belongs to bubbly flow,and the pressure at the wellhead of the central tube increased from 5.54 to 6.12 MPa during the entire transient flow stage,with an increase of 10.47%.Compared to the traditional method of using brine as the working fluid,the pump pressure rises from 2.92 to 14.01 MPa.However,if the new mode can be linked with the salt cavern gas storage and when the initial wellhead gas pressure exceeds 13 MPa,the energy consumption of the new method will be lower than that of the traditional brine-based operational mode.A new empirical formula is proposed to determine the two-phase flow pattern under different operating parameters.A special focus was given to energy consumption for oil recovery,which grows roughly in accordance with the operating pressure and oil recovery rate.However,the energy cost per volume of crude oil remains almost unchanged.This work provided a new solution for the serious brine problem and is expected to achieve petroleum recovery through natural gas displacement.
基金Project supported by the National Natural Science Foundation of China(Nos.12172169 and 12272064)the Natural Science Foundation of Jiangsu Province of China(No.BK20241773)the Priority Academic Program Development of Jiangsu Higher Education Institutions of China。
文摘Current studies on carbon nanotube (CNT) size effects predominantly employ Eringen’s differential nonlocal model, which is widely recognized as ill-suited for bounded domains. This paper investigates the free vibration of multi-walled CNTs (MWCNTs) with mathematically well-posed two-phase strain-driven and stress-driven nonlocal integral models incorporating the bi-Helmholtz kernel. The van der Waals (vdW) forces coupling MWCNT layers are similarly modeled as size-dependent via the bi-Helmholtz two-phase nonlocal integral framework. Critically, conventional pure strain-driven or stress-driven formulations become over-constrained when nonlocal vdW interactions are considered. The two-phase strategy resolves this limitation by enabling consistent coupling. Each bi-Helmholtz integral constitutive equation is equivalently transformed into a differential form requiring four additional constitutive boundary conditions (CBCs). The numerical solutions are obtained with the generalized differential quadrature method (GDQM) for these coupled higher-order equations. The parametric studies on double-walled CNTs (DWCNTs) and triple-walled CNTs (TWCNTs) elucidate the nonlocal effects predicted by both formulations. Additionally, the influence of nonlocal parameters within vdW forces is systematically evaluated to comprehensively characterize the size effects in MWCNTs.
基金Financial support from NSFC(Grant No.41572303,4151001059,41101008)Key Projects in the National Science&Technology Pillar Program(2014BAL05B01)CAS"Light of West China"Program
文摘The volume fraction of the solid and liquid phase of debris flows,which evolves simultaneously across terrains,largely determines the dynamic property of debris flows.The entrainment process significantly influences the amplitude of the volume fraction.In this paper,we present a depth-averaged two-phase debris-flow model describing the simultaneous evolution of the phase velocity and depth,the solid and fluid volume fractions and the bed morphological evolution.The model employs the Mohr–Coulomb plasticity for the solid stress,and the fluid stress is modeled as a Newtonian viscous stress.The interfacial momentum transfer includes viscous drag and buoyancy.A new extended entrainment rate formula that satisfies the boundary momentum jump condition(Iverson and Ouyang,2015)is presented.In this formula,the basal traction stress is a function of the solid volume fraction and can take advantage of both the Coulomb and velocity-dependent friction models.A finite volume method using Roe’s Riemann approximation is suggested to solve the equations.Three computational cases are conducted and compared with experiments or previous results.The results show that the current computational model and framework are robust and suitable for capturing the characteristics of debris flows.
基金National Natural Science Foundation (Project number 40604013).
文摘Biot-flow and squirt-flow are the two most important fluid flow mechanisms in porous media containing fluids. Based on the BISQ （Biot-Squirt） model where the two mechanisms are treated simultaneously, the elastic wave-field simulation in the porous medium is limited to two-dimensions and two-components （2D2C） or two-dimensions and three-components （2D3C）. There is no previous report on wave simulation in three- dimensions and three-components. Only through three dimensional numerical simulations can we have an overall understanding of wave field coupling relations and the spatial distribution characteristics between the solid and fluid phases in the dual-phase anisotropic medium. In this paper, based on the BISQ equation, we present elastic wave propagation in a three dimensional dual-phase anisotropic medium simulated by the staggered-grid high-order finite-difference method. We analyze the resulting wave fields and show that the results are an improvement.
文摘To improve the accuracy of the conventional finite-difference method, finitedifference numerical modeling methods of any even-order accuracy are recommended. We introduce any even-order accuracy difference schemes of any-order derivatives derived from Taylor series expansion. Then, a finite-difference numerical modeling method with any evenorder accuracy is utilized to simulate seismic wave propagation in two-phase anisotropic media. Results indicate that modeling accuracy improves with the increase of difference accuracy order number. It is essential to find the optimal order number, grid size, and time step to balance modeling precision and computational complexity. Four kinds of waves, static mode in the source point, SV wave cusps, reflection and transmission waves are observed in two-phase anisotropic media through modeling.
