Steel-concrete composite beams,due to their superior mechanical properties,are widely utilized in engineering structures.This study systematically investigates the calculation methods for internal forces and load-bear...Steel-concrete composite beams,due to their superior mechanical properties,are widely utilized in engineering structures.This study systematically investigates the calculation methods for internal forces and load-bearing capacity of composite beams based on elastic theory,with a focus on the transformed section method and its application under varying neutral axis positions.By deriving the geometric characteristics of the transformed section and incorporating a reduction factor accounting for slip effects,a computational model for sectional stress and ultimate load-bearing capacity is established.The results demonstrate that the slip effect significantly influences the flexural load-bearing capacity of composite beams.The proposed reduction factor,which considers the influence of the steel beam’s top flange thickness,offers higher accuracy compared to traditional methods.These findings provide a theoretical foundation for the design and analysis of composite beams,with significant practical engineering value.展开更多
This paper deals with the magnetohydrodynamic （MHD） flow of an Oldroyd 8-constant fluid in a porous medium when no-slip condition is no longer valid. Modified Darcy＇s law is used in the flow modelling. The non-line...This paper deals with the magnetohydrodynamic （MHD） flow of an Oldroyd 8-constant fluid in a porous medium when no-slip condition is no longer valid. Modified Darcy＇s law is used in the flow modelling. The non-linear differential equation with non-linear boundary conditions is solved numerically using finite difference scheme in combination with an iterative technique. Numerical results are obtained for the Couette, Poiseuille and generalized Couette flows. The effects of slip parameters on the velocity profile are discussed.展开更多
In this speculative analysis, our main focused is to address the neurotic condition that occurs due to accumulation of blood components on the wall of the artery that results in blood coagulation. Specifically, to per...In this speculative analysis, our main focused is to address the neurotic condition that occurs due to accumulation of blood components on the wall of the artery that results in blood coagulation. Specifically, to perceive this phenomena clot model is considered. To discuss this analysis mathematical model is formed in the presence of the effective thermal conductivity and variable viscosity of base fluid. Appropriate slip conditions are employed to obtain the close form solutions of temperature and velocity profile. The graphical illustrations have been presented for the assessment of pressure rise, pressure gradient and velocity profile. The effects of several parameters on the flow quantities for theoretical observation are investigated. At the end, the results confirmed that the impulsion of copper and silver nanoparticles as drug agent enlarges the amplitude of the velocity and hence nanoparticles play an important role in engineering and biomedical applications such as drug delivery system.展开更多
The Hall and ion-slip effects on fully developed electrically conducting couple stress fluid flow between vertical parallel plates in the presence of a temperature dependent heat source are investigated. The governing...The Hall and ion-slip effects on fully developed electrically conducting couple stress fluid flow between vertical parallel plates in the presence of a temperature dependent heat source are investigated. The governing non-linear partial differential equations are transformed into a system of ordinary differential equations using similarity transformations. The resulting equations are then solved using the homotopy analysis method （HAM）. The effects of the magnetic parameter, Hall parameter, ion-slip parameter and couple stress fluid parameter on velocity and temperature are discussed and shown graphically展开更多
The thermodynamic features of the Reiner-Rivlin nanoliquid flow induced by a spinning disk are analyzed numerically.The non-homogeneous two-phase nanofluid model is considered to analyze the effect of nanoparticles on...The thermodynamic features of the Reiner-Rivlin nanoliquid flow induced by a spinning disk are analyzed numerically.The non-homogeneous two-phase nanofluid model is considered to analyze the effect of nanoparticles on the thermodynamics of the Reiner-Rivlin nanomaterial,which also includes a temperature-dependent heat source(THS)and an exponential space-dependent heat source(ESHS).Further,the transfer of heat and mass is analyzed with velocity slip,volume fraction jump,and temperature jump boundary conditions.The finite difference method-based routine is used to solve the complicated differential equations formed after using the von-Karman similarity technique.Limiting cases of the present problem are found to be in good agreement with benchmarking studies.The relationship of the pertinent parameters with the heat and mass transport is scrutinized using correlation,which is further evaluated based on the probable error estimates.Multivariable models are fitted for the friction factor at the disk and heat transport,which accurately predict the dependent variables.The Reiner-Rivlin nanoliquid temperature is influenced comparatively more by the ESHS than by THS.The Nusselt number is decreased by the ESHS and THS,whereas the friction factor at the disk is predominantly decremented by the wall roughness aspect.The increment in the non-Newtonian characteristic of the liquid leads more fluid to drain away in the radial direction far from the disk compared with the fluid nearby the disk in the presence of the centrifugal force during rotation.The increased thermal and volume fraction slip lowers the nanoliquid temperature and nanoparticle volume fraction profiles.展开更多
A mathematical model for the gas-water two-phase flow in tight gas reservoirs is elaborated.The model can account for the gas slip effect,stress sensitivity,and high-speed non-Darcy factors.The related equations are s...A mathematical model for the gas-water two-phase flow in tight gas reservoirs is elaborated.The model can account for the gas slip effect,stress sensitivity,and high-speed non-Darcy factors.The related equations are solved in the framework of a finite element method.The results are validated against those obtained by using the commercial software CMG(Computer Modeling Group software for advanced recovery process simulation).It is shown that the proposed method is reliable.It can capture the fracture rejection characteristics of tight gas reservoirs better than the CMG.A sensitivity analysis of various control factors(initial water saturation,reservoir parameters,and fracturing parameters)affecting the production in tight gas wells is conducted accordingly.Finally,a series of theoretical arguments are provided for a rational and effective development/exploitation of tight sandstone gas reservoirs.展开更多
In this paper, we examine the unsteady magneto hydrodynamic (MHD) flow generated by a disc that is making non-coaxial rotations with a third grade fluid at infinity and moving with a variable acceleration. The fluid i...In this paper, we examine the unsteady magneto hydrodynamic (MHD) flow generated by a disc that is making non-coaxial rotations with a third grade fluid at infinity and moving with a variable acceleration. The fluid is assumed to satisfy slip boundary condition on the disc. The governing equations are three dimensional and highly non-linear in nature. The assumed slip boundary condition is non-linear as well. The governing equations are transformed to a nonlinear boundary value problem which is solved numerically. Comparison of this generalized problem with uniformly accelerated disk satisfying no slip condition is made. Variations of the characterizing dimensionless parameters such as slip parameter λ, acceleration parameter c, unsteady parameter τ, third grade parameter β, suction parameter S, and magnetic parameter N on the flow field are discussed and analyzed graphically.展开更多
To improve the semi-empirical model, the slip sinkage effect is analyzed based on the real vehicle test. A dynamic testing system is used to gain the dynamic responses of wheel-soil interactions, The Gauss-Newton algo...To improve the semi-empirical model, the slip sinkage effect is analyzed based on the real vehicle test. A dynamic testing system is used to gain the dynamic responses of wheel-soil interactions, The Gauss-Newton algorithm is adopted to estimate the undetermined parameters involved in the slip sinkage models. Wong＇s original model is compared with three typical slip sinkage models on the prediction performance of a drawbar pull. The maximum error rate, root mean squared error and correlation coefficient are utilized to evaluate the performance. The results indicate that the slip sinkage models outperform Wong＇s model and greatly improve the prediction accuracy. Lyasko＇s model is confirmed as an outstanding one for its comprehensive performance. Hence, the existence of the slip sinkage effect is validated. Lyasko＇s model is selected as an optimal one for the practical evaluation of military vehicle trafficability.展开更多
The aim of the present paper is to study flow and heat transfer charac- teristics of a viscous Casson thin film flow over an unsteady stretching sheet subject to variable heat flux in the presence of slip velocity con...The aim of the present paper is to study flow and heat transfer charac- teristics of a viscous Casson thin film flow over an unsteady stretching sheet subject to variable heat flux in the presence of slip velocity condition and viscous dissipation. The governing equations are partial differential equations. They are reduced to a set of highly nonlinear ordinary differential equations by suitable similarity transformations. The re- sulting similarity equations are solved numerically with a shooting method. Comparisons with previous works are macle, and the results are found to be in excellent agreement. In the present work, the effects of the unsteadiness parameter, the Casson parameter, the Eckert number, the slip velocity parameter, and the Prandtl number on flow and heat transfer characteristics are discussed. Also, the local skin-friction coefficient and the local Nusselt number at the stretching sheet are computed and discussed.展开更多
In a microfluidic system, flow slip velocity on a solid wall can be the same order of magnitude as the average velocity in a microchannel. The flow-electricity interaction in a complex microfluidic system subjected to...In a microfluidic system, flow slip velocity on a solid wall can be the same order of magnitude as the average velocity in a microchannel. The flow-electricity interaction in a complex microfluidic system subjected to joint action of wall slip and electro-viscous effect is an important topic. This paper presents an analytic solution of pressuredriven liquid flow velocity and flow-induced electric field in a two-dimensional microchannel made of different materials with wall slip and electro-viscous effects. The Poisson- Boltzmann equation and the Navier-Stokes equation are solved for the analytic solutions. The analytic solutions agree well with the numerical solutions. It was found that the wall slip amplifies the fow-induced electric field and enhances the electro-viscous effect on flow. Thus the electro-viscous effect can be significant in a relatively wide microchannel with relatively large kh, the ratio of channel width to thickness of electric double layer, in comparison with the channel without wall slip.展开更多
This study aims to investigate the correlation between the permeation effect and microfabric of the slip zone soils with Huangtupo landslide in the Three Gorges Reservoir as the study case. Based on the permeability t...This study aims to investigate the correlation between the permeation effect and microfabric of the slip zone soils with Huangtupo landslide in the Three Gorges Reservoir as the study case. Based on the permeability test and scanning electron microscope(SEM) images analysis, the fractal theory and probability entropy are used to quantify the characteristics of the remodeling specimens. First, the relationships between initial moisture content(IMC) and microstructure of the soil(percentage of particle area(PPA), pore roundness(Rp)) before and after permeability test are summarized. Then, the fractal dimension of the soil(pore distribution(Dpd), pore size(Dps)) are analyzed under the permeation effect. Based on the probability entropy, the entropy of pore(Ep) is used to characterize the porosity orientation, and the rose diagrams are used to show the particle orientation under the permeation effect. Finally, the relationship between the microstructure of the soil and its mechanical property is discussed. Results show that under the permeation effect, the microstructure of the soil has undergone tremendous changes. A flat long pore channel is formed. The order of the pore arrangement is enhanced, and soil particles switch the long axis to parallel infiltration direction to reach a new steady state. It can be inferred that the strength of soil would be weakened if the fractal dimension of soil pore decreases under any external environment.展开更多
The slip mechanism on the surface of silicon wafers under laser irradiation was studied by numerical simulations and experiments. Firstly, the slip was explained by an analysis of the generalized stacking fault energy...The slip mechanism on the surface of silicon wafers under laser irradiation was studied by numerical simulations and experiments. Firstly, the slip was explained by an analysis of the generalized stacking fault energy and the associated restoring forces. Activation of unexpected {110} slip planes was predicted to be a surface phenomenon. Experimentally,{110} slip planes were activated by changing doping concentrations of wafers and laser parameters respectively. Slip planes were {110} when slipping started within several atomic layers under the surface and turned into {111} with deeper slip.The scale effect was shown to be an intrinsic property of silicon.展开更多
This article investigates an unbiased analysis for the unsteady two-dimensional laminar flow of an incompressible, electrically and thermally conducting fluid across the space separated by two infinite rotating permea...This article investigates an unbiased analysis for the unsteady two-dimensional laminar flow of an incompressible, electrically and thermally conducting fluid across the space separated by two infinite rotating permeable walls.The influence of entropy generation, Hall and slip effects are considered within the flow analysis. The problem is modeled based on valid physical arguments and the unsteady system of dimensionless PDEs (partial differential equations) are solved with the help of Finite Difference Scheme. In the presence of pertinent parameters, the precise movement of the flow in terms of velocity, temperature, entropy generation rate, and Bejan numbers are presented graphically, which are parabolic in nature. Streamline profiles are also presented, which exemplify the accurate movement of the flow. The current study is one of the infrequent contributions to the existing literature as previous studies have not attempted to solve the system of high order non-linear PDEs for the unsteady flow with entropy generation and Hall effects in a permeable rotating channel. It is expected that the current analysis would provide a platform for solving the system of nonlinear PDEs of the other unexplored models that are associated to the two-dimensional unsteady flow in a rotating channel.展开更多
Common effect of wave and slip of internal vehicles will make rolling of the roll-on ship serious. This is one of the important reasons for overturn of ro-ro ships. The multibody system with a floating base is compose...Common effect of wave and slip of internal vehicles will make rolling of the roll-on ship serious. This is one of the important reasons for overturn of ro-ro ships. The multibody system with a floating base is composed of ro-ro ship and slipping vehicles. Takes the rolling angle of the ship and the transverse displacements of the slipping vehicles on desk as freedoms. Making use of the analysis of apparent gravitation and apparent buoyancy, the wave rolling moment is derived. By means of dynamic method of multibody system, dynamic equations of the system are established. Taking a certain channel ferry as an example, a set of numerical calculation have been carried out for rolling response of the multibody system with a floating base of a ro-ro ship and displacements response of the slipping vehicles under common effect of free slipping vehicles and wave, and a conclusion has been drawn that the motion of the numerous free slipping heavy loads will trend to be synchronous under restraining of the side-wall bulkhead with time because of repeated collision.展开更多
Nanofluids have attracted many scientists due to their remarkable thermophysical properties.Small percentage of nanoparticles when added to conventional fluid significantly enhances the heat transfer features.Sustaina...Nanofluids have attracted many scientists due to their remarkable thermophysical properties.Small percentage of nanoparticles when added to conventional fluid significantly enhances the heat transfer features.Sustainability and efficiency of nanomaterials have key role in the advancement of nanotechnology.This article analyzes the Hall,Ohmic heating and velocity slip effects on the peristalsis of nanofluid.Convective boundary conditions and heat generation/absorption are considered to facilitate the heat transfer characteristics.Governing equations for the peristaltic flow through a curved channel are derived in curvilinear coordinates.The equations are numerically solved under the assumption of long wavelength and small Reynold number.It has been observed that nanofluid enhances the heat transfer rate and reduces the fluid temperature.Hartman number and Hall parameter show reverse behavior in fluid motion and heat transfer characteristics.In the presence of velocity slip,the pressure gradient rapidly decreases and dominant effect is seen in narrow portion of channel.展开更多
The optimal design of heating and cooling systems must take into account heat radiation which is a non-linear process.In this study,the mixed convection in a radiative magnetohydrodynamic Eyring-Powell copperwater nan...The optimal design of heating and cooling systems must take into account heat radiation which is a non-linear process.In this study,the mixed convection in a radiative magnetohydrodynamic Eyring-Powell copperwater nanofluid over a stretching cylinder was investigated.The energy balance is modeled,taking into account the non-linear thermal radiation and a thermal slip condition.The effects of the embedded flow parameters on the fluid properties,as well as on the skin friction coefficient and heat transfer rate,are analyzed.Unlike in many existing studies,the recent spectral quasi-linearization method is used to solve the coupled nonlinear boundary-value problem.The computational result shows that increasing the nanoparticle volume fraction,thermal radiation parameter and heat generation parameter enhances temperature profile.We found that the velocity slip parameter and the fluid material parameter enhance the skin friction.A comparison of the current numerical results with existing literature for some limiting cases shows excellent agreement.展开更多
This article presents the mass and heat transport aspects in viscoelastic nanofluid flows under the presence of velocity slip conditions. To explore the nonNewtonian behavior, a Maxwell viscoelasticity-based micropola...This article presents the mass and heat transport aspects in viscoelastic nanofluid flows under the presence of velocity slip conditions. To explore the nonNewtonian behavior, a Maxwell viscoelasticity-based micropolar is considered. Moreover, a porous medium saturates the stretching sheet. A set of similarity variables is introduced to derive the dimensionless ordinary differential equations of velocity, concentration, and temperature profiles. The numerical solution is computed by using the MATLAB bvp4c package. The salient flow features of velocity, concentration, and temperature profiles are described and discussed through various graphs. It is observed that with an increase in the slip parameter, the micro-rotation velocity also increases. The temperature of nanoparticles gets maximum values by varying the viscoelastic parameter and the porosity parameter while an opposite trend is noted for the micro-rotation parameter. The local Nusselt number and the local Sherwood number increase by increasing the viscoelastic parameter, the porosity parameter, and the slip velocity parameter. The graphical computation is performed for a specified range of parameters, such as 0 ≤ M ≤ 2.5, 0 ≤σm ≤ 2.5, 0 ≤ K1 ≤ 1.5, 0.5 ≤ Pr ≤ 3.0, 0 ≤σ≤ 1.5, 0.5 ≤ Sc ≤ 2.0, 0.2 ≤ Nb ≤ 0.8, and 0.2 ≤ Nt ≤ 0.8.展开更多
The present work is concerned with a two-dimensional(2D)Stokes flow through a channel bounded by two parallel solid walls.The distance between the walls may be arbitrary,and the surface of one of the walls can be arbi...The present work is concerned with a two-dimensional(2D)Stokes flow through a channel bounded by two parallel solid walls.The distance between the walls may be arbitrary,and the surface of one of the walls can be arbitrarily rough.The main objective of this work consists in homogenizing the heterogeneous interface between the rough wall and fluid so as to obtain an equivalent smooth slippery fluid/solid interface characterized by an effective slip length.To solve the corresponding problem,two efficient numerical approaches are elaborated on the basis of the method of fundamental solution(MFS)and the boundary element methods(BEMs).They are applied to different cases where the fluid/solid interface is periodically or randomly rough.The results obtained by the proposed two methods are compared with those given by the finite element method and some relevant ones reported in the literature.This comparison shows that the two proposed methods are particularly efficient and accurate.展开更多
文摘Steel-concrete composite beams,due to their superior mechanical properties,are widely utilized in engineering structures.This study systematically investigates the calculation methods for internal forces and load-bearing capacity of composite beams based on elastic theory,with a focus on the transformed section method and its application under varying neutral axis positions.By deriving the geometric characteristics of the transformed section and incorporating a reduction factor accounting for slip effects,a computational model for sectional stress and ultimate load-bearing capacity is established.The results demonstrate that the slip effect significantly influences the flexural load-bearing capacity of composite beams.The proposed reduction factor,which considers the influence of the steel beam’s top flange thickness,offers higher accuracy compared to traditional methods.These findings provide a theoretical foundation for the design and analysis of composite beams,with significant practical engineering value.
文摘This paper deals with the magnetohydrodynamic （MHD） flow of an Oldroyd 8-constant fluid in a porous medium when no-slip condition is no longer valid. Modified Darcy＇s law is used in the flow modelling. The non-linear differential equation with non-linear boundary conditions is solved numerically using finite difference scheme in combination with an iterative technique. Numerical results are obtained for the Couette, Poiseuille and generalized Couette flows. The effects of slip parameters on the velocity profile are discussed.
基金the Higher Education Commission, Pakistan (HEC) for the financial support to complete this work under the research Grant No. 6170/Federal/NRPU/R&D/HEC/2016
文摘In this speculative analysis, our main focused is to address the neurotic condition that occurs due to accumulation of blood components on the wall of the artery that results in blood coagulation. Specifically, to perceive this phenomena clot model is considered. To discuss this analysis mathematical model is formed in the presence of the effective thermal conductivity and variable viscosity of base fluid. Appropriate slip conditions are employed to obtain the close form solutions of temperature and velocity profile. The graphical illustrations have been presented for the assessment of pressure rise, pressure gradient and velocity profile. The effects of several parameters on the flow quantities for theoretical observation are investigated. At the end, the results confirmed that the impulsion of copper and silver nanoparticles as drug agent enlarges the amplitude of the velocity and hence nanoparticles play an important role in engineering and biomedical applications such as drug delivery system.
文摘The Hall and ion-slip effects on fully developed electrically conducting couple stress fluid flow between vertical parallel plates in the presence of a temperature dependent heat source are investigated. The governing non-linear partial differential equations are transformed into a system of ordinary differential equations using similarity transformations. The resulting equations are then solved using the homotopy analysis method （HAM）. The effects of the magnetic parameter, Hall parameter, ion-slip parameter and couple stress fluid parameter on velocity and temperature are discussed and shown graphically
文摘The thermodynamic features of the Reiner-Rivlin nanoliquid flow induced by a spinning disk are analyzed numerically.The non-homogeneous two-phase nanofluid model is considered to analyze the effect of nanoparticles on the thermodynamics of the Reiner-Rivlin nanomaterial,which also includes a temperature-dependent heat source(THS)and an exponential space-dependent heat source(ESHS).Further,the transfer of heat and mass is analyzed with velocity slip,volume fraction jump,and temperature jump boundary conditions.The finite difference method-based routine is used to solve the complicated differential equations formed after using the von-Karman similarity technique.Limiting cases of the present problem are found to be in good agreement with benchmarking studies.The relationship of the pertinent parameters with the heat and mass transport is scrutinized using correlation,which is further evaluated based on the probable error estimates.Multivariable models are fitted for the friction factor at the disk and heat transport,which accurately predict the dependent variables.The Reiner-Rivlin nanoliquid temperature is influenced comparatively more by the ESHS than by THS.The Nusselt number is decreased by the ESHS and THS,whereas the friction factor at the disk is predominantly decremented by the wall roughness aspect.The increment in the non-Newtonian characteristic of the liquid leads more fluid to drain away in the radial direction far from the disk compared with the fluid nearby the disk in the presence of the centrifugal force during rotation.The increased thermal and volume fraction slip lowers the nanoliquid temperature and nanoparticle volume fraction profiles.
基金supported by the China Postdoctoral Science Foundation(2021M702304)and Natural Science Foundation of Shandong Province(ZR2021QE260).
文摘A mathematical model for the gas-water two-phase flow in tight gas reservoirs is elaborated.The model can account for the gas slip effect,stress sensitivity,and high-speed non-Darcy factors.The related equations are solved in the framework of a finite element method.The results are validated against those obtained by using the commercial software CMG(Computer Modeling Group software for advanced recovery process simulation).It is shown that the proposed method is reliable.It can capture the fracture rejection characteristics of tight gas reservoirs better than the CMG.A sensitivity analysis of various control factors(initial water saturation,reservoir parameters,and fracturing parameters)affecting the production in tight gas wells is conducted accordingly.Finally,a series of theoretical arguments are provided for a rational and effective development/exploitation of tight sandstone gas reservoirs.
文摘In this paper, we examine the unsteady magneto hydrodynamic (MHD) flow generated by a disc that is making non-coaxial rotations with a third grade fluid at infinity and moving with a variable acceleration. The fluid is assumed to satisfy slip boundary condition on the disc. The governing equations are three dimensional and highly non-linear in nature. The assumed slip boundary condition is non-linear as well. The governing equations are transformed to a nonlinear boundary value problem which is solved numerically. Comparison of this generalized problem with uniformly accelerated disk satisfying no slip condition is made. Variations of the characterizing dimensionless parameters such as slip parameter λ, acceleration parameter c, unsteady parameter τ, third grade parameter β, suction parameter S, and magnetic parameter N on the flow field are discussed and analyzed graphically.
基金The National Natural Science Foundation of China(No.51305078)the Science and Technology Plan of Suzhou City(No.SYG201303)
文摘To improve the semi-empirical model, the slip sinkage effect is analyzed based on the real vehicle test. A dynamic testing system is used to gain the dynamic responses of wheel-soil interactions, The Gauss-Newton algorithm is adopted to estimate the undetermined parameters involved in the slip sinkage models. Wong＇s original model is compared with three typical slip sinkage models on the prediction performance of a drawbar pull. The maximum error rate, root mean squared error and correlation coefficient are utilized to evaluate the performance. The results indicate that the slip sinkage models outperform Wong＇s model and greatly improve the prediction accuracy. Lyasko＇s model is confirmed as an outstanding one for its comprehensive performance. Hence, the existence of the slip sinkage effect is validated. Lyasko＇s model is selected as an optimal one for the practical evaluation of military vehicle trafficability.
文摘The aim of the present paper is to study flow and heat transfer charac- teristics of a viscous Casson thin film flow over an unsteady stretching sheet subject to variable heat flux in the presence of slip velocity condition and viscous dissipation. The governing equations are partial differential equations. They are reduced to a set of highly nonlinear ordinary differential equations by suitable similarity transformations. The re- sulting similarity equations are solved numerically with a shooting method. Comparisons with previous works are macle, and the results are found to be in excellent agreement. In the present work, the effects of the unsteadiness parameter, the Casson parameter, the Eckert number, the slip velocity parameter, and the Prandtl number on flow and heat transfer characteristics are discussed. Also, the local skin-friction coefficient and the local Nusselt number at the stretching sheet are computed and discussed.
基金supported by the National Natural Science Foundation of China(10872076)
文摘In a microfluidic system, flow slip velocity on a solid wall can be the same order of magnitude as the average velocity in a microchannel. The flow-electricity interaction in a complex microfluidic system subjected to joint action of wall slip and electro-viscous effect is an important topic. This paper presents an analytic solution of pressuredriven liquid flow velocity and flow-induced electric field in a two-dimensional microchannel made of different materials with wall slip and electro-viscous effects. The Poisson- Boltzmann equation and the Navier-Stokes equation are solved for the analytic solutions. The analytic solutions agree well with the numerical solutions. It was found that the wall slip amplifies the fow-induced electric field and enhances the electro-viscous effect on flow. Thus the electro-viscous effect can be significant in a relatively wide microchannel with relatively large kh, the ratio of channel width to thickness of electric double layer, in comparison with the channel without wall slip.
基金supported by the National Key R&D Program of China (2017YFC1501301)the National Natural Science Foundation of China (No. 41572278 and No. 41772310)
文摘This study aims to investigate the correlation between the permeation effect and microfabric of the slip zone soils with Huangtupo landslide in the Three Gorges Reservoir as the study case. Based on the permeability test and scanning electron microscope(SEM) images analysis, the fractal theory and probability entropy are used to quantify the characteristics of the remodeling specimens. First, the relationships between initial moisture content(IMC) and microstructure of the soil(percentage of particle area(PPA), pore roundness(Rp)) before and after permeability test are summarized. Then, the fractal dimension of the soil(pore distribution(Dpd), pore size(Dps)) are analyzed under the permeation effect. Based on the probability entropy, the entropy of pore(Ep) is used to characterize the porosity orientation, and the rose diagrams are used to show the particle orientation under the permeation effect. Finally, the relationship between the microstructure of the soil and its mechanical property is discussed. Results show that under the permeation effect, the microstructure of the soil has undergone tremendous changes. A flat long pore channel is formed. The order of the pore arrangement is enhanced, and soil particles switch the long axis to parallel infiltration direction to reach a new steady state. It can be inferred that the strength of soil would be weakened if the fractal dimension of soil pore decreases under any external environment.
基金Project supported by the National Natural Science Foundation of China(Grant No.61605079)
文摘The slip mechanism on the surface of silicon wafers under laser irradiation was studied by numerical simulations and experiments. Firstly, the slip was explained by an analysis of the generalized stacking fault energy and the associated restoring forces. Activation of unexpected {110} slip planes was predicted to be a surface phenomenon. Experimentally,{110} slip planes were activated by changing doping concentrations of wafers and laser parameters respectively. Slip planes were {110} when slipping started within several atomic layers under the surface and turned into {111} with deeper slip.The scale effect was shown to be an intrinsic property of silicon.
基金Support of the National Natural Science Foundation of China under Grant Nos.51709191 and 51706149Key Laboratory of Advanced Reactor Engineering and Safety,Ministry of Education under Grant No.ARES-2018-10
文摘This article investigates an unbiased analysis for the unsteady two-dimensional laminar flow of an incompressible, electrically and thermally conducting fluid across the space separated by two infinite rotating permeable walls.The influence of entropy generation, Hall and slip effects are considered within the flow analysis. The problem is modeled based on valid physical arguments and the unsteady system of dimensionless PDEs (partial differential equations) are solved with the help of Finite Difference Scheme. In the presence of pertinent parameters, the precise movement of the flow in terms of velocity, temperature, entropy generation rate, and Bejan numbers are presented graphically, which are parabolic in nature. Streamline profiles are also presented, which exemplify the accurate movement of the flow. The current study is one of the infrequent contributions to the existing literature as previous studies have not attempted to solve the system of high order non-linear PDEs for the unsteady flow with entropy generation and Hall effects in a permeable rotating channel. It is expected that the current analysis would provide a platform for solving the system of nonlinear PDEs of the other unexplored models that are associated to the two-dimensional unsteady flow in a rotating channel.
基金Project supported by the National Natural Science Foundation of China (No.50309018)
文摘Common effect of wave and slip of internal vehicles will make rolling of the roll-on ship serious. This is one of the important reasons for overturn of ro-ro ships. The multibody system with a floating base is composed of ro-ro ship and slipping vehicles. Takes the rolling angle of the ship and the transverse displacements of the slipping vehicles on desk as freedoms. Making use of the analysis of apparent gravitation and apparent buoyancy, the wave rolling moment is derived. By means of dynamic method of multibody system, dynamic equations of the system are established. Taking a certain channel ferry as an example, a set of numerical calculation have been carried out for rolling response of the multibody system with a floating base of a ro-ro ship and displacements response of the slipping vehicles under common effect of free slipping vehicles and wave, and a conclusion has been drawn that the motion of the numerous free slipping heavy loads will trend to be synchronous under restraining of the side-wall bulkhead with time because of repeated collision.
文摘Nanofluids have attracted many scientists due to their remarkable thermophysical properties.Small percentage of nanoparticles when added to conventional fluid significantly enhances the heat transfer features.Sustainability and efficiency of nanomaterials have key role in the advancement of nanotechnology.This article analyzes the Hall,Ohmic heating and velocity slip effects on the peristalsis of nanofluid.Convective boundary conditions and heat generation/absorption are considered to facilitate the heat transfer characteristics.Governing equations for the peristaltic flow through a curved channel are derived in curvilinear coordinates.The equations are numerically solved under the assumption of long wavelength and small Reynold number.It has been observed that nanofluid enhances the heat transfer rate and reduces the fluid temperature.Hartman number and Hall parameter show reverse behavior in fluid motion and heat transfer characteristics.In the presence of velocity slip,the pressure gradient rapidly decreases and dominant effect is seen in narrow portion of channel.
文摘The optimal design of heating and cooling systems must take into account heat radiation which is a non-linear process.In this study,the mixed convection in a radiative magnetohydrodynamic Eyring-Powell copperwater nanofluid over a stretching cylinder was investigated.The energy balance is modeled,taking into account the non-linear thermal radiation and a thermal slip condition.The effects of the embedded flow parameters on the fluid properties,as well as on the skin friction coefficient and heat transfer rate,are analyzed.Unlike in many existing studies,the recent spectral quasi-linearization method is used to solve the coupled nonlinear boundary-value problem.The computational result shows that increasing the nanoparticle volume fraction,thermal radiation parameter and heat generation parameter enhances temperature profile.We found that the velocity slip parameter and the fluid material parameter enhance the skin friction.A comparison of the current numerical results with existing literature for some limiting cases shows excellent agreement.
文摘This article presents the mass and heat transport aspects in viscoelastic nanofluid flows under the presence of velocity slip conditions. To explore the nonNewtonian behavior, a Maxwell viscoelasticity-based micropolar is considered. Moreover, a porous medium saturates the stretching sheet. A set of similarity variables is introduced to derive the dimensionless ordinary differential equations of velocity, concentration, and temperature profiles. The numerical solution is computed by using the MATLAB bvp4c package. The salient flow features of velocity, concentration, and temperature profiles are described and discussed through various graphs. It is observed that with an increase in the slip parameter, the micro-rotation velocity also increases. The temperature of nanoparticles gets maximum values by varying the viscoelastic parameter and the porosity parameter while an opposite trend is noted for the micro-rotation parameter. The local Nusselt number and the local Sherwood number increase by increasing the viscoelastic parameter, the porosity parameter, and the slip velocity parameter. The graphical computation is performed for a specified range of parameters, such as 0 ≤ M ≤ 2.5, 0 ≤σm ≤ 2.5, 0 ≤ K1 ≤ 1.5, 0.5 ≤ Pr ≤ 3.0, 0 ≤σ≤ 1.5, 0.5 ≤ Sc ≤ 2.0, 0.2 ≤ Nb ≤ 0.8, and 0.2 ≤ Nt ≤ 0.8.
基金supported by the Vietnam National Foundation for Science and Technology Development(NAFOSTED)(No.107.02-2017.310)。
文摘The present work is concerned with a two-dimensional(2D)Stokes flow through a channel bounded by two parallel solid walls.The distance between the walls may be arbitrary,and the surface of one of the walls can be arbitrarily rough.The main objective of this work consists in homogenizing the heterogeneous interface between the rough wall and fluid so as to obtain an equivalent smooth slippery fluid/solid interface characterized by an effective slip length.To solve the corresponding problem,two efficient numerical approaches are elaborated on the basis of the method of fundamental solution(MFS)and the boundary element methods(BEMs).They are applied to different cases where the fluid/solid interface is periodically or randomly rough.The results obtained by the proposed two methods are compared with those given by the finite element method and some relevant ones reported in the literature.This comparison shows that the two proposed methods are particularly efficient and accurate.
